Code
P1401
BMW
P — Powertrain
Heated Catalyst Current Too High During Heating Bank 1
Views:
UK: 22
EN: 46
RU: 30
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
DAEWOO
P — Powertrain
EGR TEMP. SENSOR
Views:
UK: 3
EN: 10
RU: 5
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
FORD
P — Powertrain
Differential Pressure Feedback Electronic Sensor Circuit High Voltage
Views:
UK: 19
EN: 44
RU: 27
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
Generic
P — Powertrain
DPFE Circuit High Input
Views:
UK: 22
EN: 42
RU: 32
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Workshop Manuals
Available brands with manuals
2
AUDI 11
6-speed manual gearbox 0B1, front-wheel drive — Workshop Manual (Edition 05.2014)
Workshop Manual199,00 UAH
Audi A3 (1997) – 1.6L 4-cylinder (2‑valve) Engine Mechanical Components Service Manual (AEH, AKL, APF) – Edition 07.2002
Workshop Manual199,00 UAH
AUDI A3 (2004) Workshop Manual — 2.0L FSI Turbo (4‑cyl, 4‑valve) Engine, Mechanics — Edition 03.2017
Workshop Manual199,00 UAH
Audi A3 2004 — Electrical System (Workshop Manual, Edition 02.2018)
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet – 4.2 l V8 (5‑valve, timing chains) – Workshop Manual (Mechanics) – Edition 04.2007
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet — Auxiliary Heater Workshop Manual (Edition 08.2004)
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet (1.8T 4‑cyl turbo) — Motronic Injection & Ignition System Service Manual (Edition 01.2015)
Workshop Manual199,00 UAH
Audi A8 (2003) — Electrical System Workshop Manual (Edition 08.2014)
Workshop Manual199,00 UAH
Audi Q4 e-tron (Type F4) - Self-study Programme SSP 685
Workshop Manual199,00 UAH
Audi Q8 (2018) — Electrical System Workshop Manual (Edition 05.2019)
Workshop Manual199,00 UAH
Audi Servicing Manual — 7‑Speed Dual Clutch Transmission 0CJ / 0CL / 0CK / 0DN / 0DP / 0HL (Edition 05.2018)
Workshop Manual199,00 UAH
LAND ROVER 3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 UAH
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
JAGUAR
P — Powertrain
Exhaust Gas Recirculation Valve Postion Circuit
Views:
UK: 22
EN: 47
RU: 29
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
KIA
P — Powertrain
EGR Control Solenoid Circuit Signal Low
Views:
UK: 28
EN: 44
RU: 33
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
LAND ROVER
P — Powertrain
Exhaust gas recirculation - restricted circuit measurement orifice valve position sensor
Views:
UK: 3
EN: 11
RU: 10
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 UAH
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
LEXUS
P — Powertrain
EGR Valve Position Sensor Circuit Malfunction
Views:
UK: 27
EN: 44
RU: 29
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
LINCOLN
P — Powertrain
Differential Pressure Feedback Electronic Sensor Circuit High Voltage
Views:
UK: 21
EN: 62
RU: 30
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
MAZDA
P — Powertrain
DPFE Sensor Circuit High Input
Views:
UK: 23
EN: 58
RU: 31
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
MERCEDES-BENZ
P — Powertrain
EGR Lifting Sender B283
Views:
UK: 11
EN: 26
RU: 20
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
MERCURY
P — Powertrain
Differential Pressure Feedback Electronic Sensor Circuit High Voltage
Views:
UK: 26
EN: 46
RU: 30
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
NISSAN
P — Powertrain
EGR Temperature Sensor
Views:
UK: 22
EN: 45
RU: 28
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
Other
P — Powertrain
DPFE Circuit High Input
Views:
UK: 23
EN: 41
RU: 27
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Workshop Manuals
Available brands with manuals
2
AUDI 11
6-speed manual gearbox 0B1, front-wheel drive — Workshop Manual (Edition 05.2014)
Workshop Manual199,00 UAH
Audi A3 (1997) – 1.6L 4-cylinder (2‑valve) Engine Mechanical Components Service Manual (AEH, AKL, APF) – Edition 07.2002
Workshop Manual199,00 UAH
AUDI A3 (2004) Workshop Manual — 2.0L FSI Turbo (4‑cyl, 4‑valve) Engine, Mechanics — Edition 03.2017
Workshop Manual199,00 UAH
Audi A3 2004 — Electrical System (Workshop Manual, Edition 02.2018)
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet – 4.2 l V8 (5‑valve, timing chains) – Workshop Manual (Mechanics) – Edition 04.2007
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet — Auxiliary Heater Workshop Manual (Edition 08.2004)
Workshop Manual199,00 UAH
Audi A4 / A4 Cabriolet (1.8T 4‑cyl turbo) — Motronic Injection & Ignition System Service Manual (Edition 01.2015)
Workshop Manual199,00 UAH
Audi A8 (2003) — Electrical System Workshop Manual (Edition 08.2014)
Workshop Manual199,00 UAH
Audi Q4 e-tron (Type F4) - Self-study Programme SSP 685
Workshop Manual199,00 UAH
Audi Q8 (2018) — Electrical System Workshop Manual (Edition 05.2019)
Workshop Manual199,00 UAH
Audi Servicing Manual — 7‑Speed Dual Clutch Transmission 0CJ / 0CL / 0CK / 0DN / 0DP / 0HL (Edition 05.2018)
Workshop Manual199,00 UAH
LAND ROVER 3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop Manual199,00 UAH
Land Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop Manual199,00 UAH
Land Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop Manual199,00 UAH
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
SUBARU
P — Powertrain
Fuel Tank Pressure Control System Performance
Views:
UK: 20
EN: 42
RU: 27
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
TOYOTA
P — Powertrain
Sub-Throttle Position Sensor Range Performance Problem
Views:
UK: 21
EN: 41
RU: 27
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P1401
VOLKSWAGEN
P — Powertrain
EGR Valve Power Stage Short To Ground
Views:
UK: 23
EN: 41
RU: 38
AI status
Completed
Completed
100%
Causes
- Shorted or low-resistance heated catalyst element (heater/sensor) on Bank 1
- Damaged wiring shorted to battery positive or poor insulation in heater harness
- Faulty heater relay or stuck relay contacts supplying continuous power
- Faulty ECM/driver transistor supplying the heater circuit
- Corroded or loose connector/ground causing abnormal current paths
- Aftermarket or incorrect replacement catalyst/heater with different resistance
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Stored or pending P1401 fault in ECU memory
- Possible failed emissions test (high catalyst heater current fault)
- Engine may enter limp/emissions protection in some models
- No obvious change in driveability in many cases (heater circuit fault is electrical)
What to check
- Retrieve freeze-frame and full DTC list and any related pending codes
- Inspect heated catalyst harness and connector at the catalyst for damage or corrosion
- Check fuses and heater relay associated with heated catalyst circuit
- Measure heater element resistance (with connector disconnected) and compare to spec
- Check for battery voltage present at heater connector when heater is OFF (short to power)
- Monitor live data: heater current, heater voltage, ECM command/duty cycle (if available)
Signal parameters
- Heater current (amps) during activation
- Heater supply voltage (volts) at connector
- Heater element resistance (ohms) at ambient temperature
- ECM commanded duty cycle or relay control state
- Fuse/relay presence (open/closed) and voltage feed to relay
Diagnostic algorithm
- Read and record all DTCs and freeze-frame data. Note whether fault is intermittent or permanent.
- Perform a careful visual inspection of the heated catalyst(s), harness routing, and connectors on Bank 1 for heat damage, chafing, corrosion, or rodent damage.
- With ignition OFF, disconnect the heated catalyst connector and measure resistance of the heater element between the heater terminals. Compare to OEM specification. A very low resistance indicates internal short.
- Check for unintended battery voltage on the heater supply wire with the connector disconnected and ignition OFF. Presence of voltage indicates a short to power or stuck relay.
- Inspect/bench-test the heated catalyst heater relay and related fuses. Replace relay if contacts appear stuck or fail bench test.
- Reconnect and with a suitable scan tool or amp clamp monitor heater current while commanding the heater ON (follow manufacturer safe procedures). Confirm overcurrent condition and capture current/voltage values.
- If wiring and relay appear OK but overcurrent persists, consider replacing the heated catalyst assembly on Bank 1 or isolating the heater harness to confirm the fault location.
- If heater and harness test within spec but fault persists, investigate ECM heater-driver circuit and related grounds. Replace ECM only after confirming external components are good and performing manufacturer-directed tests.
- After repair, clear codes and perform a functional test/drive cycle to verify the fault does not return.
Likely causes
- Internal short inside the heated catalyst assembly (failed heater element)
- Harness insulation chafed and contacting vehicle power or another hot circuit
- Heater relay stuck closed or relay control circuit shorted
- Connector terminals corroded, creating increased current draw or intermittent contact
- ECM heater driver partially failed causing improper current regulation
Fault status
Status
Heated catalyst current too high during heating for Bank 1 — overcurrent detected in heated catalyst heater circuit; MIL set.
Repair difficulty: Hard
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email