Clogged or partially blocked cylinder 7 injector nozzle from deposits or contaminated fuel; Blocked injector inlet filter or strainer on cylinder 7; Poor electrical connection or wiring fault to the cylinder 7 injector causing weak or inconsistent operation; Low fuel pressure or delivery problem affecting the bank, such as a weak pump or restricted filter; Injector internal fault such as sticking pintle or weak coil; Air leak or fault near cylinder 7 causing a similar lean reading that the ECU attributes to the injector; ECU driver fault for the cylinder 7 injector circuit.

P02B4

Cylinder 7 - 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)
B4: FaultThe specific fault in that area

What it means

P02B4 is a generic powertrain code meaning the engine control unit has detected that the fuel injector on cylinder 7 is restricted, so it is delivering less fuel than commanded. The ECU usually infers this from fuel trim, oxygen or air-fuel sensor feedback, or crankshaft speed variation showing that cylinder 7 is running lean or weak. The exact detection method and cylinder numbering depend on the engine, and the code only applies to engines with at least seven cylinders.

Symptoms

Engine management light on
Rough idle or misfire felt from one cylinder
Hesitation or flat spot under acceleration
Reduced power and poor fuel economy
Possible lean or misfire codes stored alongside
Hard starting in some cases

Possible causes

Clogged or partially blocked cylinder 7 injector nozzle from deposits or contaminated fuellikely
Blocked injector inlet filter or strainer on cylinder 7possible
Poor electrical connection or wiring fault to the cylinder 7 injector causing weak or inconsistent operationpossible
Low fuel pressure or delivery problem affecting the bank, such as a weak pump or restricted filterpossible
Injector internal fault such as sticking pintle or weak coilpossible
Air leak or fault near cylinder 7 causing a similar lean reading that the ECU attributes to the injectorrare
ECU driver fault for the cylinder 7 injector circuitrare

How to diagnose

Read all stored and pending codes and note the freeze frame data such as load, fuel trims and engine temperature
Confirm which physical cylinder is cylinder 7 for this engine using the manufacturer's firing order and layout
Inspect the injector connector, wiring and earth for damage, corrosion or looseness
Check for other fuel trim, lean or misfire codes and look at live fuel trims and misfire counters for cylinder 7
Check fuel pressure and delivery against the specification for the engine, and check the fuel filter where fitted
Check for intake or vacuum leaks near cylinder 7 with a visual inspection and smoke test
Test injector coil resistance and operating signal, and compare with the other injectors
Perform an injector flow or balance test, or swap the injector with another cylinder to see whether the fault follows it

How to fix

Clean or replace the restricted cylinder 7 injector, following the engine manufacturer's procedure
Replace the fuel filter and clear any contamination from the fuel system if contaminated fuel is found
Repair or replace damaged injector wiring or connectors
Repair fuel delivery faults such as a weak pump or pressure regulation fault
Repair any intake air leaks found
After repair, clear the codes and road test to confirm the code does not return

Can I keep driving?

Medium severity

The car can usually be driven short distances to get it checked, but it should be fixed soon. A restricted injector can cause a lean cylinder, misfire and possible engine or catalyst damage, so avoid heavy loads and stop if it runs very roughly.

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