P02D8

What it means

P02D8 means the engine control unit has learned an offset correction for the cylinder 7 fuel injector (circuit A) and that correction has reached its minimum limit. The ECU adjusts each injector's delivery to match its measured behaviour, and in this case the injector appears to be delivering more fuel than commanded, so the correction can go no lower. This code only applies to engines with at least seven cylinders, and how the offset is learned varies by manufacturer and engine.

Symptoms

• Engine management warning light on
• Rough idle or uneven running, possibly on one cylinder
• Black smoke or a strong smell of fuel from the exhaust
• Increased fuel consumption
• Hesitation or reduced power under load
• Possible misfire codes alongside the fault

Possible causes

• Cylinder 7 injector worn, leaking or delivering more fuel than commandedlikely
• Carbon or deposit build-up on the injector tip altering the spray pattern or flowpossible
• Incorrect injector data or trim values after an injector replacement that were not set up properlypossible
• Fuel pressure too high due to a fault with the regulator, pressure control or rail pressure sensorpossible
• Wiring or connector fault on the cylinder 7 injector circuit, such as high resistance or poor contactpossible
• Mechanical fault on cylinder 7 affecting combustion, such as low compression or an air leak, which the ECU tries to compensate forrare
• Outdated or faulty ECU calibration for the injector learning strategy, where the manufacturer has issued an updaterare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, paying attention to any misfire, fuel trim or fuel pressure codes
2. Check live data for cylinder 7 injector offset or correction values and compare them with the other cylinders
3. Inspect the cylinder 7 injector connector and wiring for damage, corrosion, chafing and loose pins
4. Check fuel trims and fuel rail pressure against specification at idle and under load, as the procedure and figures depend on the engine
5. Inspect for fuel leaks or fuel smell at the cylinder 7 injector and look for signs of injector sealing problems
6. Measure the injector circuit resistance and check the injector electrical operation against the manufacturer's specification
7. Carry out a compression test or cylinder balance check on cylinder 7 if the injector and fuel supply test fine
8. Check for any available manufacturer service information or calibration updates relating to injector learning

How to fix

• Replace the cylinder 7 injector if it is leaking or over-delivering, then complete any required injector coding or learning procedure
• Repair or replace damaged wiring or connectors on the injector circuit
• Correct any fuel pressure fault by repairing or replacing the faulty regulator, pressure control component or sensor
• Clean or service the injector only if the manufacturer approves it for your engine, and replace it if deposits persist
• Repair any mechanical fault found on cylinder 7
• Apply an updated ECU calibration only if the manufacturer lists an outdated calibration as a known cause for this fault

Can I keep driving?

Nearby codes

• P02D7GenericCylinder 6 Fuel Injector A Offset Learning At Max Limit
• P02D9GenericCylinder 7 Fuel Injector A Offset Learning At Max Limit