Faulty cylinder 2 fuel injector with internal short or incorrect coil resistance; Damaged wiring to the cylinder 2 injector, such as chafed insulation shorting to a power supply; Corroded, loose or damaged injector connector or ECU connector terminals; Wiring harness fault from heat, rodent damage or earlier repair work; Fault in the injector driver circuit inside the engine control unit; Outdated or faulty ECU calibration where the manufacturer has documented a driver or monitoring fault.

P0265

Cylinder 2 Injector A Circuit High.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
2: AreaFuel and air metering (injector circuit)
65: FaultThe specific fault in that area

What it means

P0265 means the engine control unit has detected a high voltage or short to voltage fault in the injector control circuit for cylinder 2. The ECU monitors the injector driver circuit and sets the code when the signal or current does not match what it expects for that injector. The exact circuit design and the way the fault is detected vary by engine and model.

Symptoms

Engine misfire or rough running, especially at idle
Illuminated check engine light
Cylinder 2 not firing or running weak
Hesitation or loss of power under load
Poor fuel economy or smell of unburnt fuel
Hard starting or engine stalling in some cases

Possible causes

Faulty cylinder 2 fuel injector with internal short or incorrect coil resistancelikely
Damaged wiring to the cylinder 2 injector, such as chafed insulation shorting to a power supplylikely
Corroded, loose or damaged injector connector or ECU connector terminalspossible
Wiring harness fault from heat, rodent damage or earlier repair workpossible
Fault in the injector driver circuit inside the engine control unitrare
Outdated or faulty ECU calibration where the manufacturer has documented a driver or monitoring faultrare

How to diagnose

Read all stored and pending codes and record the freeze frame data, noting load, engine speed and temperature when the fault set.
Check for other injector or misfire codes, as these may point to a shared supply or a wider wiring fault.
Visually inspect the cylinder 2 injector connector and wiring for chafing, heat damage, corrosion, bent pins or poor terminal tension.
Check the injector connector is secure and look for signs of fluid ingress, then clean or repair as needed.
With the ignition off, measure the cylinder 2 injector coil resistance and compare it with the manufacturer's specification for that engine.
Check the injector wiring for a short to voltage and for continuity between the injector connector and the ECU, following the wiring diagram for the model.
Compare the injector's operation with a known good injector, for example by checking the control signal with a suitable meter or scope.
Only after the injector and wiring are proven good, check the ECU supplies and grounds and look for any applicable manufacturer software updates.

How to fix

Replace the cylinder 2 injector if the resistance or operation is out of specification, following the procedure for that engine.
Repair or replace any damaged section of wiring, using proper soldered and sealed joins or a new harness section.
Clean, repair or replace corroded or damaged injector or ECU connector terminals and housings.
Update the ECU calibration only if the manufacturer lists an update for this fault.
Replace or repair the engine control unit only if the driver circuit fault is confirmed after all wiring and the injector are proven good.
Clear the code after repair and road test to confirm it does not return.

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but should be fixed soon. A misfiring or faulty injector can cause poor running, increased fuel consumption and possible damage to the catalytic converter, so avoid heavy load and long journeys.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.