Code
P1240
BUICK
P — Powertrain
Injector Circuit Cyllinder 7 Intermittent
Views:
UK: 17
EN: 36
RU: 26
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P1240
CADILLAC
P — Powertrain
Injector Circuit Cylinder 7 Intermittent
Views:
UK: 20
EN: 39
RU: 28
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P1240
CHEVROLET
P — Powertrain
Injector Circuit Cylinder 7 Intermittent
Views:
UK: 16
EN: 36
RU: 21
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P1240
CHRYSLER
P — Powertrain
Injector Circuit Cylinder 7 Intermittent
Views:
UK: 22
EN: 41
RU: 25
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
P1240
GM
P — Powertrain
Injector Circuit Cylinder 7 Intermittent
Views:
UK: 18
EN: 39
RU: 26
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
P1240
GMC
P — Powertrain
Injector Circuit Cylinder 7 Intermittent
Views:
UK: 26
EN: 52
RU: 34
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
P1240
HUMMER
P — Powertrain
Injector Circuit Cylinder 7 Intermittent
Views:
UK: 11
EN: 19
RU: 14
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
P1240
JAGUAR
P — Powertrain
Sensor Power Supply
Views:
UK: 22
EN: 41
RU: 22
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
P1240
LAND ROVER
P — Powertrain
Malfunctioning of the power supply of sensor
Views:
UK: 6
EN: 12
RU: 10
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
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Code
P1240
MINI
P — Powertrain
Manifold absolute pressure (MAP) sensor 2 - signal too low at idle
Views:
UK: 5
EN: 14
RU: 8
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
P1240
MITSUBISHI
P — Powertrain
ASC retard request plausibility
Views:
UK: 8
EN: 18
RU: 17
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
P1240
OLDSMOBILE
P — Powertrain
Injector Circuit Cylinder 7 Intermittent
Views:
UK: 17
EN: 34
RU: 22
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
P1240
Other
P — Powertrain
Sensor Power Supply Malfunction
Views:
UK: 16
EN: 34
RU: 22
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Workshop Manuals
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Workshop ManualYour experience will help others
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Code
P1240
PORSCHE
P — Powertrain
Fuel injector, cylinder 4
Views:
UK: 6
EN: 11
RU: 9
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
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Send to email
Code
P1240
RAM
P — Powertrain
CAN Communication Failure
Views:
UK: 10
EN: 11
RU: 9
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P1240
SAAB
P — Powertrain
Throttle Motor Circuit Shorted
Views:
UK: 8
EN: 11
RU: 10
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
P1240
SATURN
P — Powertrain
Injector Circuit Cyllinder 7 Intermittent
Views:
UK: 19
EN: 46
RU: 25
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
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Code
P1240
VOLKSWAGEN
P — Powertrain
Cylinder 4 Injector Circuit Open Circuit
Views:
UK: 17
EN: 37
RU: 22
AI status
Completed
Completed
100%
Causes
- Corroded, loose or damaged wiring or connector at injector 7
- Faulty fuel injector (internal short or intermittent open)
- Poor ground or supply voltage to the injector circuit
- Faulty PCM/BCM injector driver (intermittent)
- Intermittent connector contact due to heat/vibration or moisture
- Aftermarket or incorrect replacement harness/connectors
Symptoms
- Check Engine Light (MIL) may be on or flash intermittently
- Intermittent rough idle or hesitation under load
- Occasional single-cylinder misfire (possible P0307)
- Reduced fuel economy or stumble during acceleration
- Fault may clear between starts or after movement/wiggling of harness
What to check
- Read and record freeze frame and DTC history; note if P1240 is current or intermittent
- Visually inspect injector 7 connector, wiring harness and nearby grounds for damage, corrosion, pinched areas
- Back-probe injector connector and monitor injector command while cranking and running
- Measure injector resistance and compare to specification for that engine/injector
- Perform wiggle test on harness and connector while monitoring DTCs and injector signal
- Swap injector 7 with another cylinder (if practical) to see if fault follows injector
Signal parameters
- Injector command: PWM/ground-side switching pulse from PCM; pulse width varies with load — typically 1–10+ ms during running
- Expected supply voltage at injector positive terminal: ~12 V (battery voltage) with ignition ON
- Injector resistance: check service manual; common ranges: low-impedance ~2–3 Ω or high-impedance ~12–16 Ω — verify correct spec for engine
- During injector pulse the low-side driver should pull the circuit to near 0 V (ground); open/short conditions will show abnormal voltages
- Noisy, intermittent or missing pulses on oscilloscope indicate wiring, connector or driver issues
Diagnostic algorithm
- Retrieve DTC(s) and freeze frame. Confirm P1240 is stored and note operating conditions.
- Visually inspect harness and connector at injector 7 for corrosion, bent pins, water intrusion or mechanical damage.
- With ignition OFF, disconnect connector and measure injector coil resistance. Compare to manufacturer's spec. Replace if out of range.
- Reconnect, back-probe positive and negative injector terminals. With ignition ON/engine cranking or running, verify 12V supply and PCM command pulses using a multimeter or noid light. Use an oscilloscope for waveform analysis if available.
- Perform wiggle test: move wiring and connector while monitoring the injector signal and DTC status to reproduce intermittent fault.
- Check ground integrity for engine harness/PCM grounds and repair any high-resistance grounds.
- If injector and wiring check OK, swap injector 7 with another cylinder. Clear codes and run; if code follows injector, replace injector. If not, problem is wiring/driver.
- If wiring suspected, inspect along harness run, repair damaged wires, clean/replace corroded connectors, and re-secure routing to prevent chafe.
- If wiring and injector are good but intermittent persists, test PCM/driver output. Replace PCM only after confirming driver failure and following OEM procedures.
- After repairs, clear codes and perform test drive to verify no recurrence and monitor for related misfire or fuel trim issues.
Likely causes
- Corrosion or bent/loose terminal at the cylinder 7 injector connector
- Broken/shorted wiring between PCM and injector 7 (chafing, pinched)
- Injector 7 developing intermittent internal fault
- Poor ground at engine harness/grounds affecting injector return path
Fault status
Status
MIL (Check Engine) may be illuminated. P1240 stored as intermittent — fault may not be present continuously. Freeze frame data and live data can help reproduce conditions.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 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
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0
Send to email