Clogged or partially blocked fuel injector on cylinder 11 from deposits or contamination; Poor quality or contaminated fuel causing deposits or restricted spray; Low fuel pressure or restricted fuel supply, such as a blocked filter or weak pump, affecting delivery; Wiring or connector fault at the cylinder 11 injector, such as high resistance or a poor terminal contact; Injector driver fault or internal control unit issue for that cylinder; Mechanical fault on that cylinder, such as a vacuum leak at its intake runner or a compression problem, skewing the monitoring result.

P02C4

Cylinder 11 - Injector Restricted.

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)
C4: FaultThe specific fault in that area

What it means

P02C4 is the generic code for a restricted injector on cylinder 11, so it only applies to engines with at least eleven cylinders. The engine control unit has found that the fuel delivered by that injector is lower than commanded. It usually reaches this conclusion from fuel trim, cylinder balance or injector flow monitoring, and the method varies by engine.

Symptoms

Rough idle or a noticeable misfire
Hesitation or lack of power under load
Engine management light on
Poor fuel economy
Hard starting or uneven running when cold
Possible lean or misfire codes stored alongside

Possible causes

Clogged or partially blocked fuel injector on cylinder 11 from deposits or contaminationlikely
Poor quality or contaminated fuel causing deposits or restricted spraypossible
Low fuel pressure or restricted fuel supply, such as a blocked filter or weak pump, affecting deliverypossible
Wiring or connector fault at the cylinder 11 injector, such as high resistance or a poor terminal contactpossible
Injector driver fault or internal control unit issue for that cylinderrare
Mechanical fault on that cylinder, such as a vacuum leak at its intake runner or a compression problem, skewing the monitoring resultrare

How to diagnose

Read all stored codes and freeze frame data, noting engine load, temperature and fuel trims when the code set, and look for related misfire or fuel trim codes
Check the fuel quality and history, including recent refuelling and any signs of water or contamination
Inspect the cylinder 11 injector connector and wiring for damage, corrosion, looseness and heat damage
Check live data for fuel trims, misfire counters and any injector balance or correction values, comparing cylinder 11 with the others
Measure fuel pressure against the manufacturer's specification and check the fuel filter if fitted, as the procedure depends on the engine
Test the injector electrical resistance and driver signal against specification, then compare with a neighbouring injector
Perform an injector flow or leak-down test, or swap the injector with another cylinder to see whether the fault follows it
Check for intake leaks near cylinder 11 and carry out a compression or leak-down test if the injector tests good

How to fix

Clean or replace the restricted cylinder 11 injector, following the manufacturer's procedure and any coding requirements
Drain and replace contaminated fuel, then replace the fuel filter if fitted
Repair or replace the faulty fuel pump or regulator if fuel pressure is low
Repair damaged wiring or replace the corroded connector or terminals at the injector
Repair intake leaks or underlying mechanical faults found on that cylinder
Replace or repair the control unit only if the driver fault is confirmed after all other checks

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but get it checked soon. A restricted injector can cause a lean cylinder or misfire, which may overheat the catalytic converter and damage the engine; avoid heavy load, and stop 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.