Code
P1404
ALFA ROMEO
P — Powertrain
TL4226 circuit fault
Views:
UK: 4
EN: 6
RU: 6
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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Code
P1404
BMW
P — Powertrain
Heated Catalyst Current Too High During Heating Bank 2
Views:
UK: 21
EN: 29
RU: 22
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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Code
P1404
BUICK
P — Powertrain
Exhaust Gas Recirculation System Valve 2
Views:
UK: 15
EN: 26
RU: 23
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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Code
P1404
CADILLAC
P — Powertrain
Exhaust Gas Recirculation System Valve 2
Views:
UK: 18
EN: 28
RU: 23
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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Code
P1404
CHEVROLET
P — Powertrain
Exhaust Gas Recirculation System Valve 2
Views:
UK: 21
EN: 27
RU: 24
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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Code
P1404
CHRYSLER
P — Powertrain
Exhaust Gas Recirculation System Valve 2
Views:
UK: 17
EN: 30
RU: 22
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
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Code
P1404
FIAT
P — Powertrain
TL4226 circuit fault
Views:
UK: 2
EN: 7
RU: 5
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
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Code
P1404
FORD
P — Powertrain
IAT - B Circuit Malfunction Exhaust Gas Recirculation Closed Position Performance
Views:
UK: 17
EN: 25
RU: 27
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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Code
P1404
Generic
P — Powertrain
IAT - B Circuit Malfunction/ Exhaust Gas Recirculation Closed Position Performance
Views:
UK: 18
EN: 28
RU: 22
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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Code
P1404
GM
P — Powertrain
Exhaust Gas Recirculation System Valve 2
Views:
UK: 19
EN: 29
RU: 21
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
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Code
P1404
GMC
P — Powertrain
Exhaust Gas Recirculation System Valve 2
Views:
UK: 17
EN: 31
RU: 22
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
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Code
P1404
HUMMER
P — Powertrain
Exhaust Gas Recirculation (EGR) Closed Position Performance
Views:
UK: 6
EN: 14
RU: 9
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
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Code
P1404
ISUZU
P — Powertrain
Exhaust Gas Recirculation (EGR) Closed Position Performance
Views:
UK: 9
EN: 19
RU: 18
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
Your experience will help others
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Was this AI description helpful?
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Code
P1404
LINCOLN
P — Powertrain
IAT B Circuit Malfunction Exhaust Gas Recirculation Closed Position Performance
Views:
UK: 20
EN: 29
RU: 25
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
Your experience will help others
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Was this AI description helpful?
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👍 Like
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Send to email
Code
P1404
MERCEDES-BENZ
P — Powertrain
EGR Control
Views:
UK: 8
EN: 16
RU: 16
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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Code
P1404
MERCURY
P — Powertrain
IAT B Circuit Malfunction Exhaust Gas Recirculation Closed Position Performance
Views:
UK: 20
EN: 29
RU: 24
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
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Code
P1404
OLDSMOBILE
P — Powertrain
Exhaust Gas Recirculation System Valve 2
Views:
UK: 22
EN: 29
RU: 27
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
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Code
P1404
Other
P — Powertrain
IAT - B Circuit Malfunction/ Exhaust Gas Recirculation Closed Position Performance
Views:
UK: 24
EN: 33
RU: 30
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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Code
P1404
PLYMOUTH
P — Powertrain
Exhaust Gas Recirculation System Valve 2
Views:
UK: 16
EN: 26
RU: 22
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
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Was this AI description helpful?
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0
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Code
P1404
PONTIAC
P — Powertrain
Exhaust Gas Recirculation System Valve 2
Views:
UK: 19
EN: 29
RU: 25
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
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👍 Like
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Code
P1404
RAM
P — Powertrain
EGR Close Position Performance
Views:
UK: 4
EN: 7
RU: 2
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
Your experience will help others
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Was this AI description helpful?
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👍 Like
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0
Send to email
Code
P1404
SATURN
P — Powertrain
Exhaust Gas Recirculation System Valve 2
Views:
UK: 21
EN: 31
RU: 24
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
Similar codes
Your experience will help others
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0
Send to email
Code
P1404
VOLKSWAGEN
P — Powertrain
EGR Flow Adaptation Not Carried Out
Views:
UK: 21
EN: 26
RU: 21
AI status
Completed
Completed
100%
Causes
- Open circuit in TL4226 wiring (broken wire, disconnected connector)
- Short to battery or short to ground in TL4226 circuit
- Corroded or damaged connector pins or terminals
- Failed TL4226 component (valve/solenoid/sensor)
- Poor or missing ground at component or ECU
- Blown fuse or faulty relay supplying the circuit
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Related system operates intermittently or not at all
- Rough idle, hesitation or reduced engine performance
- Possible limp-home or reduced power mode
- Stored P1404 code (may be accompanied by other codes)
- Symptoms may be intermittent and worsen with vibration or moisture
What to check
- Read and record freeze-frame and related stored codes using a scan tool
- Identify TL4226 component and pinout from factory wiring diagrams
- Visually inspect connector, pins and wiring for damage, corrosion, or water
- Check fuses and relays that supply the TL4226 circuit
- Back-probe connector and check for battery voltage on power pin (key ON)
- Verify good ground at component and chassis ground points
Signal parameters
- Supply voltage (power pin) — near battery voltage with key ON (approx. 12 V); confirm against factory spec
- Ground reference — near 0 V at ground terminal
- Control signal — often a switched or PWM signal from ECM; voltage may vary 0–12 V depending on duty cycle
- Coil or actuator resistance — typical solenoids 10–100 ohms (consult service manual for TL4226 exact value)
- Intermittent/oscillating waveform possible when ECM is modulating the device; use oscilloscope for best results
Diagnostic algorithm
- Connect a professional scan tool. Read and record P1404 and any other stored/ pending codes and freeze-frame data.
- Consult Alfa Romeo service documentation to identify the TL4226 component, wiring colors, connector pinout and exact signal/resistance specs.
- Perform a thorough visual inspection of the TL4226 connector and harness route (look for chafing, heat damage, oil or water contamination).
- With key OFF, disconnect the TL4226 connector and inspect pins for corrosion, bent/pushed-out pins or contamination. Clean or repair as needed.
- Check supply circuit: with key ON (engine OFF) back-probe the power pin for battery voltage and check the fuse/relay feeding it.
- Check ground: measure voltage drop between TL4226 ground and a known good chassis ground while circuit is operating; verify solid
- Measure the device resistance (with connector disconnected) and compare to factory specification. Replace component if out of tolerance.
- Check control signal: with connector connected and engine running or system commanded, back-probe the control pin. Use a lab scope if available to verify proper waveform/PWM and duty cycle per factory data.
- Perform a wiggle test along harness while monitoring live data or DTCs to confirm intermittent faults. Repair any damaged wiring/harness and secure routing.
- If wiring and component check good, verify continuity between TL4226 connector and corresponding ECM pins; repair any open/shorts.
- If wiring and device are OK but fault persists, consider ECM driver fault — verify other ECM-driven circuits and consult factory diagnostics before replacing ECM.
- After repairs, clear codes and perform functional test / road test to confirm the fault does not return.
Likely causes
- Corroded/damaged connector or pin (common failure point)
- Open or shorted wire in the harness between TL4226 and ECM
- Failed TL4226 device (coil/sensor out of specification)
- Poor ground at component or chassis ground point
- Blown fuse or related power supply interruption
Fault status
Status
TL4226 circuit fault detected — electrical signal out of specification (open/short/intermittent). Inspect wiring, connector, device and fuses/grounds before replacing control unit.
Repair difficulty: Medium
Diagnostic time: 1.0-2.5 hours
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