Cylinder 2 injector with internal short or low coil resistance; Injector wiring chafed or shorted to earth between the injector and the ECU; Corroded, loose or damaged injector connector or ECU connector terminals; Water ingress or oil contamination in the injector harness or connector; Faulty injector driver inside the ECU; Harness damaged by heat or rubbing against engine components.

P0264

Cylinder 2 Injector A Circuit Low.

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)
64: FaultThe specific fault in that area

What it means

P0264 means the engine control unit has detected a low voltage or low signal state in the control circuit for the cylinder 2 fuel injector. The ECU monitors the injector driver circuit and sets the code when the voltage or current is lower than expected, which points to a short to earth, a wiring fault or a failing injector or driver. The exact circuit layout and test values depend on the engine and whether it is petrol or diesel.

Symptoms

Engine misfire or rough running, especially at idle
Malfunction indicator lamp on
Noticeable loss of power or hesitation
Hard starting or engine cranks but cylinder 2 does not fire
Raw fuel smell or poor fuel economy
Engine may enter limp mode on some models

Possible causes

Cylinder 2 injector with internal short or low coil resistancelikely
Injector wiring chafed or shorted to earth between the injector and the ECUlikely
Corroded, loose or damaged injector connector or ECU connector terminalspossible
Water ingress or oil contamination in the injector harness or connectorpossible
Faulty injector driver inside the ECUrare
Harness damaged by heat or rubbing against engine componentspossible

How to diagnose

Read all stored and pending codes and note the freeze frame data, then check for other injector or misfire codes such as P0302
Visually inspect the cylinder 2 injector connector and the surrounding harness for chafing, heat damage, corrosion or water ingress
Disconnect and reseat the injector connector, checking the terminals for tightness and contamination
Measure the injector coil resistance and compare it with the manufacturer specification for that engine
Check the injector feed and control wires for a short to earth with the connector unplugged and the ignition off
Swap the cylinder 2 injector with another cylinder if the design allows, clear the code and see whether the fault follows the injector
Check the injector driver signal with a suitable test instrument or lab scope while cranking
Check the ECU connector pins and, only after everything else is ruled out, consider an ECU fault

How to fix

Replace the cylinder 2 injector if its resistance or operation is out of specification
Repair or replace the damaged section of wiring and secure it away from heat and abrasion
Clean or replace corroded connector terminals or the injector connector
Dry out and seal the harness and connector after fixing the source of water or oil ingress
Repair or replace the ECU only if the driver fault is confirmed after all wiring and injector tests pass

Can I keep driving?

Medium severity

Short, gentle journeys are possible, but get it checked soon. A dead or misfiring cylinder can overload the catalytic converter and cause further damage, and in some cases the injector may stick open and wash oil from the bore.

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