Code
P0268
Generic
P — Powertrain
Cylinder 3 Injector A Circuit High
Views:
UK: 26
EN: 42
RU: 46
AI status
Completed
Completed
100%
Causes
- Short to battery voltage on injector A circuit (cylinder 3)
- Failed or internally shorted fuel injector (cylinder 3)
- Bad connector (corrosion, bent pins, water intrusion)
- Damaged wiring (chafing, pinched, melted insulation)
- Poor or missing PCM/ECM ground or power supply
- Faulty PCM/ECM driver transistor
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Rough idle or misfire on cylinder 3
- Loss of power or poor acceleration
- Hard starting or increased cranking time
- Increased fuel consumption or smoke (diesel)
- Possible engine vibration localized to cylinder 3
What to check
- Read freeze frame/fault data and confirm P0268 is current or stored
- Visual inspection of injector connector, wiring harness and nearby components for damage or contamination
- Backprobe injector connector and check for battery voltage, signal voltage and continuity to PCM
- Measure injector coil resistance at the connector (compare to spec/service manual)
- Wiggle test wiring while monitoring live data or voltages to reproduce fault
- Swap injector with another cylinder (if identical) to see if code follows the injector
Signal parameters
- Injector coil resistance: typical ranges — diesel low-res injectors ~0.5–3 Ω; gasoline high-res injectors ~10–16 Ω. Consult vehicle service manual for exact spec.
- Key ON (engine OFF): injector connector normally shows battery voltage on the supply side; driver side should not be at battery voltage unless commanded or shorted.
- When commanded ON: PCM usually switches the driver to ground (sinks current) — expect pulsed ground; voltage will drop across coil accordingly.
- Pulse width: varies with rpm/load — typically 1–10 ms at idle to longer under load (use scan tool for live PW values).
- If circuit is ‘high’: measured voltage or current is higher than expected or driver cannot pull the circuit low; may see near-battery voltage on driver output or abnormally high current draw.
Diagnostic algorithm
- Confirm code and retrieve related codes and freeze-frame data. Note engine conditions when DTC set.
- Perform visual inspection of cylinder 3 injector connector, wiring harness, and nearby components for damage, heat, oil/water ingress or pin corrosion.
- With ignition OFF, disconnect injector connector and measure injector coil resistance across injector pins. Compare to spec.
- Check for short to battery: measure resistance from injector driver pin to battery positive; low resistance indicates short to B+.
- With key ON (engine OFF) backprobe connector: verify supply voltage at the injector supply pin and check driver pin behavior while commanding the injector with a scan tool.
- Start engine and monitor injector command (pulse width) and voltage/current while inducing load or using a wiggle test to locate intermittent faults.
- Swap the cylinder 3 injector with a known good one from another cylinder (if identical) and see if the code follows the injector — if it does, replace the injector.
- If code remains on original cylinder after swap, check harness continuity to PCM, inspect PCM connector for damage and test PCM driver output and ground circuits.
- Repair any wiring/connectors or replace faulty injector as indicated. If wiring and injector check good, suspect PCM and confirm with manufacturer diagnostics before replacement.
- Clear codes and perform a road/functional test to verify the repair and ensure the code does not return.
Likely causes
- Wiring short to B+ at or near the cylinder 3 injector connector
- Corroded/loose connector at the injector
- Failed injector with internal short
- PCM driver failure (less common)
Fault status
Status
PCM detected high voltage/current on Cylinder 3 Injector A circuit and stored fault P0268. MIL illuminated. Investigation of injector, wiring, connectors and PCM driver required.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
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Code
P0268
GWM
P — Powertrain
- High Cylinder 3 Cylinder Chain
Views:
UK: 8
EN: 18
RU: 17
AI status
Completed
Completed
100%
Causes
- Short to battery voltage on injector A circuit (cylinder 3)
- Failed or internally shorted fuel injector (cylinder 3)
- Bad connector (corrosion, bent pins, water intrusion)
- Damaged wiring (chafing, pinched, melted insulation)
- Poor or missing PCM/ECM ground or power supply
- Faulty PCM/ECM driver transistor
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Rough idle or misfire on cylinder 3
- Loss of power or poor acceleration
- Hard starting or increased cranking time
- Increased fuel consumption or smoke (diesel)
- Possible engine vibration localized to cylinder 3
What to check
- Read freeze frame/fault data and confirm P0268 is current or stored
- Visual inspection of injector connector, wiring harness and nearby components for damage or contamination
- Backprobe injector connector and check for battery voltage, signal voltage and continuity to PCM
- Measure injector coil resistance at the connector (compare to spec/service manual)
- Wiggle test wiring while monitoring live data or voltages to reproduce fault
- Swap injector with another cylinder (if identical) to see if code follows the injector
Signal parameters
- Injector coil resistance: typical ranges — diesel low-res injectors ~0.5–3 Ω; gasoline high-res injectors ~10–16 Ω. Consult vehicle service manual for exact spec.
- Key ON (engine OFF): injector connector normally shows battery voltage on the supply side; driver side should not be at battery voltage unless commanded or shorted.
- When commanded ON: PCM usually switches the driver to ground (sinks current) — expect pulsed ground; voltage will drop across coil accordingly.
- Pulse width: varies with rpm/load — typically 1–10 ms at idle to longer under load (use scan tool for live PW values).
- If circuit is ‘high’: measured voltage or current is higher than expected or driver cannot pull the circuit low; may see near-battery voltage on driver output or abnormally high current draw.
Diagnostic algorithm
- Confirm code and retrieve related codes and freeze-frame data. Note engine conditions when DTC set.
- Perform visual inspection of cylinder 3 injector connector, wiring harness, and nearby components for damage, heat, oil/water ingress or pin corrosion.
- With ignition OFF, disconnect injector connector and measure injector coil resistance across injector pins. Compare to spec.
- Check for short to battery: measure resistance from injector driver pin to battery positive; low resistance indicates short to B+.
- With key ON (engine OFF) backprobe connector: verify supply voltage at the injector supply pin and check driver pin behavior while commanding the injector with a scan tool.
- Start engine and monitor injector command (pulse width) and voltage/current while inducing load or using a wiggle test to locate intermittent faults.
- Swap the cylinder 3 injector with a known good one from another cylinder (if identical) and see if the code follows the injector — if it does, replace the injector.
- If code remains on original cylinder after swap, check harness continuity to PCM, inspect PCM connector for damage and test PCM driver output and ground circuits.
- Repair any wiring/connectors or replace faulty injector as indicated. If wiring and injector check good, suspect PCM and confirm with manufacturer diagnostics before replacement.
- Clear codes and perform a road/functional test to verify the repair and ensure the code does not return.
Likely causes
- Wiring short to B+ at or near the cylinder 3 injector connector
- Corroded/loose connector at the injector
- Failed injector with internal short
- PCM driver failure (less common)
Fault status
Status
PCM detected high voltage/current on Cylinder 3 Injector A circuit and stored fault P0268. MIL illuminated. Investigation of injector, wiring, connectors and PCM driver required.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
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Code
P0268
HUMMER
P — Powertrain
Cylinder 3 Injector Circuit High
Views:
UK: 19
EN: 23
RU: 24
AI status
Completed
Completed
100%
Causes
- Short to battery voltage on injector A circuit (cylinder 3)
- Failed or internally shorted fuel injector (cylinder 3)
- Bad connector (corrosion, bent pins, water intrusion)
- Damaged wiring (chafing, pinched, melted insulation)
- Poor or missing PCM/ECM ground or power supply
- Faulty PCM/ECM driver transistor
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Rough idle or misfire on cylinder 3
- Loss of power or poor acceleration
- Hard starting or increased cranking time
- Increased fuel consumption or smoke (diesel)
- Possible engine vibration localized to cylinder 3
What to check
- Read freeze frame/fault data and confirm P0268 is current or stored
- Visual inspection of injector connector, wiring harness and nearby components for damage or contamination
- Backprobe injector connector and check for battery voltage, signal voltage and continuity to PCM
- Measure injector coil resistance at the connector (compare to spec/service manual)
- Wiggle test wiring while monitoring live data or voltages to reproduce fault
- Swap injector with another cylinder (if identical) to see if code follows the injector
Signal parameters
- Injector coil resistance: typical ranges — diesel low-res injectors ~0.5–3 Ω; gasoline high-res injectors ~10–16 Ω. Consult vehicle service manual for exact spec.
- Key ON (engine OFF): injector connector normally shows battery voltage on the supply side; driver side should not be at battery voltage unless commanded or shorted.
- When commanded ON: PCM usually switches the driver to ground (sinks current) — expect pulsed ground; voltage will drop across coil accordingly.
- Pulse width: varies with rpm/load — typically 1–10 ms at idle to longer under load (use scan tool for live PW values).
- If circuit is ‘high’: measured voltage or current is higher than expected or driver cannot pull the circuit low; may see near-battery voltage on driver output or abnormally high current draw.
Diagnostic algorithm
- Confirm code and retrieve related codes and freeze-frame data. Note engine conditions when DTC set.
- Perform visual inspection of cylinder 3 injector connector, wiring harness, and nearby components for damage, heat, oil/water ingress or pin corrosion.
- With ignition OFF, disconnect injector connector and measure injector coil resistance across injector pins. Compare to spec.
- Check for short to battery: measure resistance from injector driver pin to battery positive; low resistance indicates short to B+.
- With key ON (engine OFF) backprobe connector: verify supply voltage at the injector supply pin and check driver pin behavior while commanding the injector with a scan tool.
- Start engine and monitor injector command (pulse width) and voltage/current while inducing load or using a wiggle test to locate intermittent faults.
- Swap the cylinder 3 injector with a known good one from another cylinder (if identical) and see if the code follows the injector — if it does, replace the injector.
- If code remains on original cylinder after swap, check harness continuity to PCM, inspect PCM connector for damage and test PCM driver output and ground circuits.
- Repair any wiring/connectors or replace faulty injector as indicated. If wiring and injector check good, suspect PCM and confirm with manufacturer diagnostics before replacement.
- Clear codes and perform a road/functional test to verify the repair and ensure the code does not return.
Likely causes
- Wiring short to B+ at or near the cylinder 3 injector connector
- Corroded/loose connector at the injector
- Failed injector with internal short
- PCM driver failure (less common)
Fault status
Status
PCM detected high voltage/current on Cylinder 3 Injector A circuit and stored fault P0268. MIL illuminated. Investigation of injector, wiring, connectors and PCM driver required.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
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Code
P0268
LAND ROVER
P — Powertrain
high cylinder injector circuit
Views:
UK: 13
EN: 25
RU: 23
AI status
Completed
Completed
100%
Causes
- Short to battery voltage on injector A circuit (cylinder 3)
- Failed or internally shorted fuel injector (cylinder 3)
- Bad connector (corrosion, bent pins, water intrusion)
- Damaged wiring (chafing, pinched, melted insulation)
- Poor or missing PCM/ECM ground or power supply
- Faulty PCM/ECM driver transistor
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Rough idle or misfire on cylinder 3
- Loss of power or poor acceleration
- Hard starting or increased cranking time
- Increased fuel consumption or smoke (diesel)
- Possible engine vibration localized to cylinder 3
What to check
- Read freeze frame/fault data and confirm P0268 is current or stored
- Visual inspection of injector connector, wiring harness and nearby components for damage or contamination
- Backprobe injector connector and check for battery voltage, signal voltage and continuity to PCM
- Measure injector coil resistance at the connector (compare to spec/service manual)
- Wiggle test wiring while monitoring live data or voltages to reproduce fault
- Swap injector with another cylinder (if identical) to see if code follows the injector
Signal parameters
- Injector coil resistance: typical ranges — diesel low-res injectors ~0.5–3 Ω; gasoline high-res injectors ~10–16 Ω. Consult vehicle service manual for exact spec.
- Key ON (engine OFF): injector connector normally shows battery voltage on the supply side; driver side should not be at battery voltage unless commanded or shorted.
- When commanded ON: PCM usually switches the driver to ground (sinks current) — expect pulsed ground; voltage will drop across coil accordingly.
- Pulse width: varies with rpm/load — typically 1–10 ms at idle to longer under load (use scan tool for live PW values).
- If circuit is ‘high’: measured voltage or current is higher than expected or driver cannot pull the circuit low; may see near-battery voltage on driver output or abnormally high current draw.
Diagnostic algorithm
- Confirm code and retrieve related codes and freeze-frame data. Note engine conditions when DTC set.
- Perform visual inspection of cylinder 3 injector connector, wiring harness, and nearby components for damage, heat, oil/water ingress or pin corrosion.
- With ignition OFF, disconnect injector connector and measure injector coil resistance across injector pins. Compare to spec.
- Check for short to battery: measure resistance from injector driver pin to battery positive; low resistance indicates short to B+.
- With key ON (engine OFF) backprobe connector: verify supply voltage at the injector supply pin and check driver pin behavior while commanding the injector with a scan tool.
- Start engine and monitor injector command (pulse width) and voltage/current while inducing load or using a wiggle test to locate intermittent faults.
- Swap the cylinder 3 injector with a known good one from another cylinder (if identical) and see if the code follows the injector — if it does, replace the injector.
- If code remains on original cylinder after swap, check harness continuity to PCM, inspect PCM connector for damage and test PCM driver output and ground circuits.
- Repair any wiring/connectors or replace faulty injector as indicated. If wiring and injector check good, suspect PCM and confirm with manufacturer diagnostics before replacement.
- Clear codes and perform a road/functional test to verify the repair and ensure the code does not return.
Likely causes
- Wiring short to B+ at or near the cylinder 3 injector connector
- Corroded/loose connector at the injector
- Failed injector with internal short
- PCM driver failure (less common)
Fault status
Status
PCM detected high voltage/current on Cylinder 3 Injector A circuit and stored fault P0268. MIL illuminated. Investigation of injector, wiring, connectors and PCM driver required.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
Similar codes
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