Cylinder 5 injector leaking or flowing more than its rated amount (worn, dirty or sticking open); Injector electrical fault such as high resistance, poor connector contact or damaged wiring to cylinder 5; Fuel pressure too high or fuel rail pressure control fault affecting fuelling; Mechanical problem on cylinder 5 (reduced compression, valve or ignition fault) causing the control unit to compensate incorrectly; Carbon build-up or contamination in the cylinder 5 intake port or injector tip changing spray pattern; Outdated or faulty engine control unit calibration or internal driver fault (model and engine dependent).

P02D4

Cylinder 5 Fuel Injector A Offset Learning At Min Limit.

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)
D4: FaultThe specific fault in that area

What it means

P02D4 is a generic powertrain code meaning the engine control unit has reached the minimum limit of its learned offset correction for the cylinder 5 fuel injector (injector A). The control unit trims each injector's delivery to correct small differences in flow, and for cylinder 5 it has run out of room to reduce fuelling any further. This usually points to that injector delivering more fuel than commanded, or to a fault that makes the cylinder behave as if it is running rich.

Symptoms

Engine management light on
Rough idle or uneven running, particularly when warm
Slight misfire or hesitation under light load
Higher than normal fuel consumption
Smell of unburnt fuel or sooty exhaust
Possible additional misfire or fuel trim codes stored

Possible causes

Cylinder 5 injector leaking or flowing more than its rated amount (worn, dirty or sticking open)likely
Injector electrical fault such as high resistance, poor connector contact or damaged wiring to cylinder 5possible
Fuel pressure too high or fuel rail pressure control fault affecting fuellingpossible
Mechanical problem on cylinder 5 (reduced compression, valve or ignition fault) causing the control unit to compensate incorrectlypossible
Carbon build-up or contamination in the cylinder 5 intake port or injector tip changing spray patternpossible
Outdated or faulty engine control unit calibration or internal driver fault (model and engine dependent)rare

How to diagnose

Read all stored codes and freeze frame data, and note any related misfire, fuel trim or rail pressure codes
Check for technical service bulletins or software updates relevant to the vehicle and engine
Inspect the cylinder 5 injector connector and wiring for damage, corrosion, heat damage or loose pins
Measure the injector coil resistance and compare it with the manufacturer specification for the engine
View live data for cylinder 5 injector correction values and compare with the other cylinders
Check fuel rail pressure against specification at idle and under load, following the model-specific procedure
Perform a cylinder balance or compression test, and check the spark plug or glow plug condition on cylinder 5
Test the injector for leak-down and spray pattern, or swap it with another cylinder to see whether the fault follows

How to fix

Replace the faulty cylinder 5 injector and carry out any injector learning or coding procedure the manufacturer requires
Repair or replace damaged wiring or connectors to the injector
Correct fuel pressure faults by repairing the faulty regulator, pump or sensor as diagnosed
Repair the underlying mechanical or ignition fault on cylinder 5
Clean the intake port or injector area where contamination is confirmed, following the manufacturer's procedure
Update the engine control unit calibration where an outdated version is a known cause

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but book it in soon. Persistent over-fuelling can wash oil from the cylinder wall, dilute the engine oil and damage the catalytic converter, so avoid heavy loads and stop driving if it runs very roughly or the engine light flashes.

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