P0274: Cylinder 5 Injector Circuit High
May cause rough idle, misfire on cylinder 5, loss of power and increased emissions
Overview
P0274 generic OBD-II code indicating the engine control module has detected high voltage or abnormal current draw in the fuel injector circuit for cylinder #5, often due to wiring issues, faulty injector, or ECM driver problems
Common Symptoms
- Check Engine Light illuminated
- Rough idle and engine vibration
- Loss of power or poor acceleration
- Reduced fuel economy
- Possible cylinder 5 misfire
Most Common Causes
Injector may have internal short or open causing abnormal current draw
Connector corrosion or chafed wiring can cause high circuit voltage readings
Poor ground or alternator/battery voltage spikes can impact injector circuit readings
Internal driver transistor or MOSFET failure in the control module can set P0274
Diagnostic Steps
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Retrieve freeze-frame and live data with OBD-II scannerExpected: Record P0274 and look for related misfire codes (e.g., P0305)Interpretation: Confirms the code and checks if the issue is isolated to cylinder 5
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Visually inspect wiring and connectors to cylinder 5 injectorExpected: Look for broken wires, corrosion, loose connectorsInterpretation: If wiring damage is found, repair and retest
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Measure resistance of cylinder 5 injector with multimeterExpected: Injector resistance within manufacturer spec (e.g., ~11–18 ohms)Interpretation: Out-of-spec resistance suggests a faulty injector
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Perform voltage supply test at injector connector (engine running)Expected: Voltage within expected range (per OEM spec)Interpretation: High/abnormal voltage indicates wiring or PCM driver issue
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Swap suspected injector with another cylinder (if applicable)Expected: Code follows the injector if injector is faultyInterpretation: Helps distinguish between injector vs. wiring/ECM issue
Repair Solutions
Typical fix if wiring harness or connector is faulty
Cost varies by vehicle and injector type
ECM replacement and programming may be required in rare cases
Common Misdiagnoses
Avoid these common diagnostic mistakes:
- Assuming low fuel pressure or general misfire without checking cylinder-specific injector circuit
- Replacing ECM without isolating wiring or injector fault
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