P02D5

What it means

P02D5 means the engine control unit has adjusted the fuel delivery correction (offset learning) for the cylinder 5 injector as far as it is allowed to go and still sees a difference from the target. The learned offset has hit its maximum limit, so the injector is delivering noticeably more or less fuel than commanded, or something else is affecting cylinder 5 in a similar way. The exact learning method and limits depend on the engine and fuel system.

Symptoms

• Engine management light on
• Rough idle or misfire felt on one cylinder
• Hesitation or reduced power under load
• Increased fuel consumption
• Hard starting or uneven running when cold
• Possible smell of fuel or black smoke from the exhaust

Possible causes

• Worn, sticking or leaking cylinder 5 fuel injector delivering the wrong quantitylikely
• Carbon or deposit build-up on the injector tip or in the cylinder 5 combustion chamberpossible
• Wiring or connector fault on the cylinder 5 injector circuit (high resistance, corrosion, chafing)possible
• Mechanical problem on cylinder 5 such as low compression or a valve sealing fault, which upsets the learned correctionpossible
• Fuel pressure or supply fault affecting delivery (pump, regulator, rail pressure), depending on the fuel systempossible
• Injector was replaced or coded incorrectly, or the learned values were not reset or relearned after the repairpossible
• Outdated or faulty engine control unit calibration, where the manufacturer has issued a fixrare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting load, temperature and fuel trim values at the time the code set.
2. Check for related codes such as misfire, fuel pressure, or other injector offset codes, and treat those first if present.
3. Inspect the cylinder 5 injector connector and wiring for damage, corrosion, loose pins, oil contamination or chafing.
4. View live data for cylinder 5 injector correction or misfire counters and compare with the other cylinders at idle and under load.
5. Check fuel pressure against the manufacturer specification, and look for fuel leaks or signs of injector leakage.
6. Measure injector circuit resistance and check the feed and control signals against the manufacturer data for the engine.
7. Carry out a compression or leak-down test on cylinder 5 if the correction stays at its limit with a healthy injector.
8. Check whether any injector was recently replaced and whether its correction data was entered and relearned as the manufacturer requires.

How to fix

• Repair or replace damaged wiring, terminals or the connector on the cylinder 5 injector circuit.
• Replace the cylinder 5 injector if it is faulty, then carry out any required coding and learning procedure.
• Clean or remove carbon deposits using the manufacturer-approved method where deposits are the cause.
• Repair any fuel supply or pressure fault found, such as a failing pump or regulator.
• Repair the underlying mechanical fault on cylinder 5 if compression or valve sealing is poor.
• Update the control unit software only if the manufacturer lists an outdated calibration as a known cause, then clear the code and confirm it does not return.

Can I keep driving?

Nearby codes

• P02D4GenericCylinder 5 Fuel Injector A Offset Learning At Min Limit
• P02D6GenericCylinder 6 Fuel Injector A Offset Learning At Min Limit