Clogged or restricted fuel injector nozzle due to fuel contamination or deposits; Failed or sticking fuel injector solenoid winding; Damaged or corroded electrical connector at the injector; Chafed or open injector wiring harness; Faulty powertrain control module driver circuit for that injector; Low fuel pressure or a restricted fuel filter affecting all injectors, though the code may set on the weakest cylinder first

DTC codes / P02xx · Fuel and air metering (injector circuits) / P02C4

P02C4Cylinder 11 - Injector Restricted

Q: What does code P02C4 mean?

Cylinder 11 - Injector Restricted. P02C4 indicates that the powertrain control module has detected an abnormal restriction in the fuel injector circuit for cylinder 11, typically by monitoring current or voltage feedback and finding it outside the expected range. The code means the injector is not flowing the commanded amount of fuel, which can cause a misfire or a lean condition on that cylinder.

P02C4 indicates that the powertrain control module has detected an abnormal restriction in the fuel injector circuit for cylinder 11, typically by monitoring current or voltage feedback and finding it outside the expected range. The code means the injector is not flowing the commanded amount of fuel, which can cause a misfire or a lean condition on that cylinder.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or a noticeable vibration that may be worse when the engine is cold
Engine misfire, sometimes felt as a stumble or hesitation during acceleration
Reduced engine power or poor fuel economy
A strong raw fuel smell from the exhaust if the injector is stuck partially open or leaking
Hard starting or an engine that stalls shortly after startup

Common causes, most likely first

Clogged or restricted fuel injector nozzle due to fuel contamination or deposits
Failed or sticking fuel injector solenoid winding
Damaged or corroded electrical connector at the injector
Chafed or open injector wiring harness
Faulty powertrain control module driver circuit for that injector
Low fuel pressure or a restricted fuel filter affecting all injectors, though the code may set on the weakest cylinder first

How to diagnose and fix it

Perform a visual inspection of the cylinder 11 injector connector and wiring for corrosion, chafing, or loose pins
Measure the injector coil resistance with a multimeter and compare it to the manufacturer's specification
Check fuel pressure and volume at the rail to rule out a supply issue before condemning the injector
Use a noid light or oscilloscope to verify the injector pulse signal from the powertrain control module
Run a fuel injector balance test or cylinder contribution test to confirm the injector is restricted
Remove and professionally clean or replace the restricted injector, then clear the code and verify the repair with a road test

What the code does not always mean

A P02C4 can be set by a poor electrical connection at the injector even when the injector itself is mechanically sound, so always check the connector before replacing parts.
Fuel contamination from a failing fuel pump or a bad batch of fuel can restrict multiple injectors, but the code may only flag cylinder 11 first because it is the most sensitive to the imbalance.
A restricted injector on cylinder 11 can cause a lean misfire that mimics an ignition coil fault, so swapping coils without checking injector balance often leads to a misdiagnosis.
On engines with cylinder deactivation, a P02C4 may appear only when the cylinder is reactivated, and the injector may test fine when the engine is idling on all cylinders.
The powertrain control module driver circuit for the injector can fail intermittently, setting the code only under certain temperature or vibration conditions, which makes a simple resistance check misleading.

Can I keep driving with P02C4?

You can usually drive the vehicle short distances to a repair shop, but avoid heavy acceleration, towing, or prolonged idling because a restricted injector can cause a lean misfire that damages the catalytic converter over time. If the check engine light begins flashing or the engine runs very rough, stop driving and have the vehicle towed.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.