P0274
Cylinder 5 Injector Circuit HighP0274 is a generic OBD-II powertrain diagnostic trouble code: Cylinder 5 Injector Circuit High. It is logged by the engine control unit when the fuel/inj monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P0274 means
P0274 is set when the ECM/PCM detects that the voltage on the cylinder 5 fuel injector control circuit exceeds the manufacturer's upper threshold. Under normal operation the ECM driver pulls the injector circuit to ground to open the solenoid; a circuit-high condition indicates the circuit is seeing an elevated voltage that prevents or disrupts normal driver operation. Common causes include a short-to-voltage in the harness, an internally shorted injector solenoid drawing excessive current and producing back-EMF spikes, or a failed ECM driver transistor.
Cylinder 5 is present in five-cylinder engines (Audi/VW 2.5 R5, Volvo five-cylinders), inline-six engines (BMW N52/N54/B58, Mercedes M256, Cummins 5.9/6.7), and V8 and larger engines where cylinder 5 is typically the first cylinder on Bank 2. The physical location varies considerably between these layouts, affecting both diagnosis and repair complexity.
Like all injector circuit-high conditions, P0274 can cause the affected cylinder to misfire or over-fuel unpredictably. Unburned fuel entering the exhaust can overheat and damage the catalytic converter, so prompt diagnosis is recommended.
Common causes
Most-frequently reported root causes when P0274 is logged.
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1
Faulty cylinder 5 fuel injector with an internally shorted solenoid coil creating excessive current draw.
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2
Short-to-voltage fault in the cylinder 5 injector harness — chafed wire insulation contacting a 12 V supply.
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3
Corroded or loose injector connector generating abnormal resistance and voltage fluctuations.
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4
Restricted or blocked injector nozzle causing abnormal back-pressure and a resulting back-EMF spike on the circuit.
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5
Failed ECM internal driver transistor for the cylinder 5 channel, allowing circuit voltage to float above the acceptable range.
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6
Cross-contamination between injector wiring circuits caused by damaged harness insulation near the ECM connector.
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7
Incorrect replacement injector installed with coil impedance outside the ECM's design specification.
Symptoms drivers notice
How to diagnose P0274
A typical diagnostic flow when this code is present.
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1
Record all stored DTCs and freeze-frame data; confirm the code recurs after clearing with a road test.
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2
Visually inspect the cylinder 5 injector harness for chafed, melted, or pinched insulation that could cause contact with a power source.
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3
Check the injector connector for corrosion, bent or backed-out pins, and proper latching.
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4
Measure injector coil resistance against the OEM specification — a short-circuit condition will read well below the lower limit.
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5
With the harness disconnected at the injector, check for voltage present on the signal wire with the ignition off; any voltage here confirms a short-to-power in the harness.
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6
Swap the cylinder 5 injector with a known-good unit from an adjacent cylinder; if the fault code moves to the new cylinder location, the injector is faulty — if it stays at cylinder 5, the harness or ECM driver is at fault.
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7
Use an oscilloscope on the ECM side of the injector harness to evaluate the driver waveform before replacing the ECM, as module replacement is costly and the fault is more likely to lie in the harness or injector.
Related powertrain codes
- P0065 — Air Assisted Injector Control Range/Performance
- P0066 — Air Assisted Injector Control Circuit or Circuit Low
- P0067 — Air Assisted Injector Control Circuit High
- P0087 — Fuel Rail/System Pressure - Too Low
- P0088 — Fuel Rail/System Pressure - Too High
- P0089 — Fuel Pressure Regulator 1 Performance
Frequently asked questions
What is the difference between P0273 (low) and P0274 (high) for cylinder 5?
P0273 indicates the injector circuit voltage is below the minimum — typically an open circuit, broken wire, or dead injector coil. P0274 indicates it is above the maximum — usually a short to a voltage source in the harness or a shorted injector solenoid. Both codes prevent correct injector operation but require different diagnostic approaches.
Can P0274 damage my catalytic converter?
Yes. If cylinder 5 is misfiring due to the circuit fault, raw unburned fuel or a rich exhaust gas mixture enters the catalytic converter. Sustained misfire can overheat the catalyst substrate and cause permanent damage within a relatively short driving distance.
My vehicle is a V8 — where exactly is cylinder 5?
On most V8 engines cylinder 5 is the first cylinder on Bank 2 (the bank opposite cylinder 1). The exact numbering convention varies by manufacturer — always confirm using the vehicle-specific service manual or a cylinder numbering diagram for your engine family before testing.
The injector and wiring both test fine. Could the ECM be causing P0274?
Yes, though it is uncommon. If injector coil resistance, harness continuity, and insulation integrity all pass inspection, connect an oscilloscope to the ECM injector driver pin. A corrupted or high-voltage waveform with no harness fault present points to an internal ECM driver failure. Confirm with a specialist before purchasing a replacement ECM.
Disabling P0274 in software
RaceTune can permanently disable P0274 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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