Code
P0295
Generic
P — Powertrain
Cylinder 12 Injector A Circuit High
Views:
UK: 10
EN: 14
RU: 14
AI status
Completed
Completed
100%
Causes
- Short to battery/ignition voltage on the injector control circuit
- Open or corroded connector or pin at the injector or ECM
- Damaged wiring harness (chafing, broken conductor, water intrusion)
- Failed fuel injector (internal short or leakage)
- Faulty PCM/ECM driver transistor or internal electronics
- Blown fuse or faulty relay supplying injector circuits
Symptoms
- Malfunction Indicator Lamp (MIL) or Check Engine light illuminated
- Rough idle or misfire on cylinder 12
- Reduced engine power, hesitation or poor acceleration
- Increased fuel consumption and emissions
- Hard start or no-start if circuit is seriously compromised
- Intermittent faults that may clear with engine cycles
What to check
- Read freeze-frame and all stored/ pending codes with a scan tool; note related misfire or injector codes
- Perform a visual inspection of injector 12 connector, wiring harness, and nearby components for damage or corrosion
- Check for obvious blown fuses or relays feeding the injector bank
- Measure voltage at the injector connector (back-probe) with key on and during cranking
- Measure injector coil resistance at the injector and compare to factory spec (or swap with a known-good injector)
- Perform continuity checks between injector pin and ECM pin, and check for short to battery or ground
Signal parameters
- Resting (inactive) signal voltage: approximately battery voltage (~12 V) on a typical low-side driven injector circuit (verify with factory data)
- Active signal: pulsed to near 0 V (ground) during injector activation; pulse width varies with rpm/load
- Typical injector coil resistance: consult vehicle/factory spec (gasoline port injectors often ~10–16 Ω; diesel injectors or heavy duty coils can be much lower)
- Expected waveform: clean, repeatable pulses with consistent dwell/pulse width and sharp transitions; no sustained high-voltage condition
- If signal shows continuous high voltage (stuck at battery voltage) or noise/spikes, suspect short or driver fault
Diagnostic algorithm
- Record DTC(s), freeze-frame data and any related misfire/ injector codes. Verify engine conditions when code set.
- Visually inspect connector, wiring harness and pins at cylinder 12 injector and ECM for corrosion, bent pins or damage.
- Check fuses/relays that supply injector power; replace if blown and re-test.
- Back-probe the injector connector with key ON and engine OFF: verify reference/supply and control signal voltages match expected idle values.
- Measure injector coil resistance at the connector; compare to factory spec. If out of range, remove and bench-test the injector per service procedures.
- Check continuity between the injector control pin and the ECM pin; check for short to battery and short to ground using a multimeter.
- Use an oscilloscope on the control wire while cranking/running to confirm proper pulsed waveform and to identify high-voltage anomalies or noise.
- If waveform and wiring checks are normal, swap injector 12 with another cylinder’s injector (if serviceable and identical) and see if the code follows the injector or stays with cylinder 12.
- If code follows the injector, replace the faulty injector. If code stays on cylinder 12, repair wiring/connector or replace ECM if bench-tested and confirmed faulty.
- After repairs, clear codes, perform functional verification and test drive under conditions that originally set the code. Re-scan for recurrence.
Likely causes
- Corroded or loose connector at cylinder 12 injector
- Wiring shorted to constant 12 V (pin pushed, insulation worn)
- Failed injector with internal short to battery
- Open or high-resistance return/ground in injector circuit
- Intermittent ECM driver failure (less common)
Fault status
Status
Stored when the PCM/ECM detects a higher-than-expected voltage or abnormal signal on Injector A circuit for cylinder 12. MIL illuminated. Fault may be steady or intermittent depending on wiring/connector condition or driver performance.
Repair difficulty: Medium
Diagnostic time: 1.0 - 3.0 hours
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Code
P0295
GWM
P — Powertrain
- High Cylinder Injector 12 Circuit High
Views:
UK: 2
EN: 2
RU: 1
AI status
Completed
Completed
100%
Causes
- Short to battery/ignition voltage on the injector control circuit
- Open or corroded connector or pin at the injector or ECM
- Damaged wiring harness (chafing, broken conductor, water intrusion)
- Failed fuel injector (internal short or leakage)
- Faulty PCM/ECM driver transistor or internal electronics
- Blown fuse or faulty relay supplying injector circuits
Symptoms
- Malfunction Indicator Lamp (MIL) or Check Engine light illuminated
- Rough idle or misfire on cylinder 12
- Reduced engine power, hesitation or poor acceleration
- Increased fuel consumption and emissions
- Hard start or no-start if circuit is seriously compromised
- Intermittent faults that may clear with engine cycles
What to check
- Read freeze-frame and all stored/ pending codes with a scan tool; note related misfire or injector codes
- Perform a visual inspection of injector 12 connector, wiring harness, and nearby components for damage or corrosion
- Check for obvious blown fuses or relays feeding the injector bank
- Measure voltage at the injector connector (back-probe) with key on and during cranking
- Measure injector coil resistance at the injector and compare to factory spec (or swap with a known-good injector)
- Perform continuity checks between injector pin and ECM pin, and check for short to battery or ground
Signal parameters
- Resting (inactive) signal voltage: approximately battery voltage (~12 V) on a typical low-side driven injector circuit (verify with factory data)
- Active signal: pulsed to near 0 V (ground) during injector activation; pulse width varies with rpm/load
- Typical injector coil resistance: consult vehicle/factory spec (gasoline port injectors often ~10–16 Ω; diesel injectors or heavy duty coils can be much lower)
- Expected waveform: clean, repeatable pulses with consistent dwell/pulse width and sharp transitions; no sustained high-voltage condition
- If signal shows continuous high voltage (stuck at battery voltage) or noise/spikes, suspect short or driver fault
Diagnostic algorithm
- Record DTC(s), freeze-frame data and any related misfire/ injector codes. Verify engine conditions when code set.
- Visually inspect connector, wiring harness and pins at cylinder 12 injector and ECM for corrosion, bent pins or damage.
- Check fuses/relays that supply injector power; replace if blown and re-test.
- Back-probe the injector connector with key ON and engine OFF: verify reference/supply and control signal voltages match expected idle values.
- Measure injector coil resistance at the connector; compare to factory spec. If out of range, remove and bench-test the injector per service procedures.
- Check continuity between the injector control pin and the ECM pin; check for short to battery and short to ground using a multimeter.
- Use an oscilloscope on the control wire while cranking/running to confirm proper pulsed waveform and to identify high-voltage anomalies or noise.
- If waveform and wiring checks are normal, swap injector 12 with another cylinder’s injector (if serviceable and identical) and see if the code follows the injector or stays with cylinder 12.
- If code follows the injector, replace the faulty injector. If code stays on cylinder 12, repair wiring/connector or replace ECM if bench-tested and confirmed faulty.
- After repairs, clear codes, perform functional verification and test drive under conditions that originally set the code. Re-scan for recurrence.
Likely causes
- Corroded or loose connector at cylinder 12 injector
- Wiring shorted to constant 12 V (pin pushed, insulation worn)
- Failed injector with internal short to battery
- Open or high-resistance return/ground in injector circuit
- Intermittent ECM driver failure (less common)
Fault status
Status
Stored when the PCM/ECM detects a higher-than-expected voltage or abnormal signal on Injector A circuit for cylinder 12. MIL illuminated. Fault may be steady or intermittent depending on wiring/connector condition or driver performance.
Repair difficulty: Medium
Diagnostic time: 1.0 - 3.0 hours
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Code
P0295
HUMMER
P — Powertrain
Cylinder 12 Injector Circuit High
Views:
UK: 7
EN: 13
RU: 5
AI status
Completed
Completed
100%
Causes
- Short to battery/ignition voltage on the injector control circuit
- Open or corroded connector or pin at the injector or ECM
- Damaged wiring harness (chafing, broken conductor, water intrusion)
- Failed fuel injector (internal short or leakage)
- Faulty PCM/ECM driver transistor or internal electronics
- Blown fuse or faulty relay supplying injector circuits
Symptoms
- Malfunction Indicator Lamp (MIL) or Check Engine light illuminated
- Rough idle or misfire on cylinder 12
- Reduced engine power, hesitation or poor acceleration
- Increased fuel consumption and emissions
- Hard start or no-start if circuit is seriously compromised
- Intermittent faults that may clear with engine cycles
What to check
- Read freeze-frame and all stored/ pending codes with a scan tool; note related misfire or injector codes
- Perform a visual inspection of injector 12 connector, wiring harness, and nearby components for damage or corrosion
- Check for obvious blown fuses or relays feeding the injector bank
- Measure voltage at the injector connector (back-probe) with key on and during cranking
- Measure injector coil resistance at the injector and compare to factory spec (or swap with a known-good injector)
- Perform continuity checks between injector pin and ECM pin, and check for short to battery or ground
Signal parameters
- Resting (inactive) signal voltage: approximately battery voltage (~12 V) on a typical low-side driven injector circuit (verify with factory data)
- Active signal: pulsed to near 0 V (ground) during injector activation; pulse width varies with rpm/load
- Typical injector coil resistance: consult vehicle/factory spec (gasoline port injectors often ~10–16 Ω; diesel injectors or heavy duty coils can be much lower)
- Expected waveform: clean, repeatable pulses with consistent dwell/pulse width and sharp transitions; no sustained high-voltage condition
- If signal shows continuous high voltage (stuck at battery voltage) or noise/spikes, suspect short or driver fault
Diagnostic algorithm
- Record DTC(s), freeze-frame data and any related misfire/ injector codes. Verify engine conditions when code set.
- Visually inspect connector, wiring harness and pins at cylinder 12 injector and ECM for corrosion, bent pins or damage.
- Check fuses/relays that supply injector power; replace if blown and re-test.
- Back-probe the injector connector with key ON and engine OFF: verify reference/supply and control signal voltages match expected idle values.
- Measure injector coil resistance at the connector; compare to factory spec. If out of range, remove and bench-test the injector per service procedures.
- Check continuity between the injector control pin and the ECM pin; check for short to battery and short to ground using a multimeter.
- Use an oscilloscope on the control wire while cranking/running to confirm proper pulsed waveform and to identify high-voltage anomalies or noise.
- If waveform and wiring checks are normal, swap injector 12 with another cylinder’s injector (if serviceable and identical) and see if the code follows the injector or stays with cylinder 12.
- If code follows the injector, replace the faulty injector. If code stays on cylinder 12, repair wiring/connector or replace ECM if bench-tested and confirmed faulty.
- After repairs, clear codes, perform functional verification and test drive under conditions that originally set the code. Re-scan for recurrence.
Likely causes
- Corroded or loose connector at cylinder 12 injector
- Wiring shorted to constant 12 V (pin pushed, insulation worn)
- Failed injector with internal short to battery
- Open or high-resistance return/ground in injector circuit
- Intermittent ECM driver failure (less common)
Fault status
Status
Stored when the PCM/ECM detects a higher-than-expected voltage or abnormal signal on Injector A circuit for cylinder 12. MIL illuminated. Fault may be steady or intermittent depending on wiring/connector condition or driver performance.
Repair difficulty: Medium
Diagnostic time: 1.0 - 3.0 hours
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