Fuel and air

P02DF — Cylinder 10 Fuel Injector Offset Learning at Max Limit

Severity: medium Drive with care, to a shop

What P02DF means

The engine control module continuously trims each injector's opening time so every cylinder gets the same air-fuel mixture. For cylinder 10, that correction has reached its maximum allowed value and cannot go any further. It means the injector is delivering noticeably more or less fuel than commanded, or something else is upsetting the mixture in that cylinder. This code only applies to engines with 10 or more cylinders.

Symptoms

  • Check Engine Light on
  • Rough idle
  • Misfire or stumbling
  • Higher fuel consumption
  • Hesitation or reduced power
  • Increased exhaust emissions

Possible causes

  1. Clogged or worn cylinder 10 fuel injector
  2. Damaged injector wiring or a poor connector contact
  3. Low or inconsistent fuel pressure (pump, filter, regulator)
  4. Air leak in the intake near that cylinder
  5. Mechanical problem in cylinder 10 (compression, valves)
  6. ECM software or calibration issue (unlikely)

How to diagnose

  1. Read all codes and freeze frame data and look for other fuel trim or misfire codes
  2. Review short and long term fuel trims and per-cylinder adaptation values
  3. Inspect the cylinder 10 injector connector and harness for corrosion, chafing or breaks
  4. Test injector resistance and the control signal with a scope or noid light
  5. Measure fuel pressure at idle and under load
  6. Check for intake vacuum leaks and exhaust leaks, using a smoke machine if possible
  7. Compare cylinder performance: injector balance, compression, spark plug condition
  8. Swap the injector with a neighboring cylinder and see whether the fault follows it

Common fixes

  • Clean or replace the cylinder 10 injector
  • Repair the injector wiring or connector
  • Replace the fuel filter and fix the cause of low fuel pressure
  • Repair any air leaks
  • Reset adaptations and update ECM software if an update exists

Questions and answers

What does P02DF mean?

The control module has used up its adjustment range for the cylinder 10 injector and can no longer compensate for the fuel delivery error. The cause is usually the injector, its circuit or fuel pressure.

Can I drive with P02DF?

Briefly, if the engine runs smoothly. If it misfires or the check engine light flashes, stop driving to avoid damaging the catalytic converter.

Will clearing the code fix it?

No. Until the root cause is fixed, the adaptation will reach its limit again and the code will return. Find the injector, wiring or fuel supply fault first.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.