Faulty cylinder 2 fuel injector (internal coil or driver fault, or mechanical fault); Damaged, chafed or corroded wiring to the cylinder 2 injector, including high resistance or a short; Poor connection at the injector plug or engine control unit connector (corrosion, bent or loose terminals); Low or unstable battery or system voltage affecting injector drive; Fault in the injector driver stage inside the engine control unit; Outdated or faulty control unit calibration, where the manufacturer has issued a known update for this code.

P02EF

Cylinder 2 Injector Circuit Range/Performance.

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)
EF: FaultThe specific fault in that area

What it means

P02EF is a generic code meaning the engine control unit has found the cylinder 2 fuel injector circuit operating outside its expected range or performance. The control unit monitors the injector drive circuit and its feedback, and this fault is set when the electrical behaviour does not match what it commanded. The exact monitoring strategy and the fuel system type it applies to vary by manufacturer and engine.

Symptoms

Engine warning light on
Rough idle or misfire on cylinder 2
Hesitation or reduced power under load
Poor fuel economy
Hard starting or extended cranking
Engine running in a limited performance mode

Possible causes

Faulty cylinder 2 fuel injector (internal coil or driver fault, or mechanical fault)likely
Damaged, chafed or corroded wiring to the cylinder 2 injector, including high resistance or a shortlikely
Poor connection at the injector plug or engine control unit connector (corrosion, bent or loose terminals)likely
Low or unstable battery or system voltage affecting injector drivepossible
Fault in the injector driver stage inside the engine control unitrare
Outdated or faulty control unit calibration, where the manufacturer has issued a known update for this coderare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting engine load, temperature and voltage when the fault set; look for related misfire or other injector codes.
Check battery condition and charging voltage, as low voltage can upset injector circuit monitoring.
Visually inspect the cylinder 2 injector connector and wiring for chafing, heat damage, oil contamination, corrosion and loose terminals.
Check live data for cylinder 2 misfire counts and fuel trims, and compare with the other cylinders.
Measure the injector coil resistance and compare it with the manufacturer's specification for that engine.
Test the injector wiring for continuity, short to earth and short to supply between the injector and control unit, following the wiring diagram for the model.
Swap the cylinder 2 injector with another cylinder where practical and see whether the fault or misfire follows it.
Check for a published calibration update or technical bulletin for this code on the specific model and engine.

How to fix

Replace the cylinder 2 injector if it is out of specification or faulty, following the correct procedure for the engine, including any coding or adaptation it requires.
Repair or replace damaged wiring between the injector and control unit.
Clean or renew corroded or loose connector terminals and secure the connector properly.
Restore correct battery and charging system condition if voltage is low or unstable.
Apply a manufacturer-issued control unit calibration update only where one is documented for this fault.
Repair or replace the engine control unit only after wiring and injector faults have been ruled out and the driver fault is confirmed.

Can I keep driving?

Medium severity

Short, gentle journeys are usually possible, but get it checked soon because a faulty injector can cause misfires, poor running and possible catalyst damage. Avoid heavy load and stop driving if the engine runs very roughly or the warning light flashes.

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