Cylinder 1 injector with an internal short or fault; Wiring harness chafed or shorted to a power supply in the injector control circuit; Corroded, damaged or loose injector connector or ECU connector terminals; Fault in the injector driver inside the engine control unit; Wrong voltage supply to the injector circuit, such as a fault in a relay or fuse feed (depends on the model); Water ingress or oil contamination in the harness or connector.

P0262

Cylinder 1 Injector A Circuit High.

Generic
Powertrain
Generic code
High severity

How this code is built

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

What it means

P0262 means the engine control unit has detected a high voltage or short to voltage in the control circuit for the cylinder 1 fuel injector. The ECU monitors the injector circuit and sets the code when the voltage or current is higher than expected, which points to a wiring short to power or an internal fault in the injector or driver. The exact circuit layout and how the fault is detected depend on the engine and whether it is petrol or diesel.

Symptoms

Engine management light on
Misfire or rough running, often on cylinder 1
Engine cutting out or refusing to start
Poor performance or reduced power, possibly limp mode
Noticeably worse fuel economy
Smell of fuel or raw fuel in the exhaust

Possible causes

Cylinder 1 injector with an internal short or faultlikely
Wiring harness chafed or shorted to a power supply in the injector control circuitlikely
Corroded, damaged or loose injector connector or ECU connector terminalspossible
Fault in the injector driver inside the engine control unitpossible
Wrong voltage supply to the injector circuit, such as a fault in a relay or fuse feed (depends on the model)possible
Water ingress or oil contamination in the harness or connectorrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including engine load, temperature and speed when the fault set
Check for other injector or misfire codes to see whether the fault is limited to cylinder 1
Visually inspect the cylinder 1 injector connector and the nearby harness for chafing, heat damage, oil contamination, corrosion and bent or pushed-back terminals
Clear the code and see how quickly it returns, wiggling the harness and connector while the engine runs to look for an intermittent fault
Measure the injector coil resistance and compare it with the manufacturer specification for that engine
Check the injector supply voltage and the control wire for a short to voltage using the wiring diagram for the vehicle
With the ECU connector disconnected, test the wiring between the injector and the ECU for continuity and shorts to power
Swap the injector with another cylinder if the design allows, and see whether the fault follows it, before suspecting the ECU

How to fix

Replace the cylinder 1 injector if it fails resistance or swap tests, and carry out any adaptation or coding the manufacturer requires for that engine
Repair or replace the damaged section of wiring and secure it clear of heat and abrasion
Clean or replace corroded or damaged connectors and terminals
Restore the correct supply by repairing or replacing a faulty relay, fuse or feed wiring where that is the cause
Repair or replace the engine control unit only after the wiring and injector are proven good, and in line with the manufacturer's procedure

Can I keep driving?

High severity

Avoid driving until it is diagnosed. A shorted injector circuit can cause a severe misfire, unburnt fuel in the exhaust that can damage the catalytic converter, and in some cases the injector may stay open and risk engine damage.

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