Fuel and air

P02D1 — Cylinder 3 Fuel Injector Offset Learning at Max Limit

Severity: medium Drive with care, to a shop

What P02D1 means

The engine control module continually adjusts how long each injector stays open so every cylinder gets the right amount of fuel. P02D1 means the learned correction for the cylinder 3 injector has reached its maximum allowed value, so the module cannot compensate any further. Most often the injector is not delivering the fuel quantity the ECM expects.

Symptoms

  • Check engine light on
  • Rough idle
  • Misfire, especially on cylinder 3
  • Reduced power and sluggish acceleration
  • Higher fuel consumption
  • Hesitation under throttle

Possible causes

  1. Dirty, clogged or worn cylinder 3 injector
  2. Damaged wiring or poor connection at injector 3
  3. Faulty injector driver circuit in the ECM
  4. Low or unstable fuel pressure
  5. Intake air leak upsetting the mixture
  6. Mechanical cylinder problem affecting combustion

How to diagnose

  1. Scan all codes and freeze frame data, and look for misfire codes
  2. Review short and long term fuel trims and injector learned values
  3. Compare cylinder balance and contribution of cylinder 3 to the others
  4. Inspect the injector 3 connector and harness, and measure injector resistance
  5. Check the injector control signal with a scope or noid light
  6. Test fuel pressure and how well it holds after shutdown
  7. Inspect the intake and exhaust for leaks
  8. If needed, swap injectors and see whether the fault follows

Common fixes

  • Clean or replace the cylinder 3 injector
  • Repair the wiring or replace the connector
  • Fix the cause of low fuel pressure (pump, filter, regulator)
  • Repair intake air leaks
  • Reset adaptations and, if confirmed faulty, reflash or replace the ECM

Questions and answers

What does P02D1 mean?

The ECM found that the correction for the cylinder 3 injector has reached its maximum limit. That points to a fuel delivery deviation in that cylinder.

Can I drive with P02D1?

Briefly and gently, for example to a shop, is usually fine. If the engine misfires, avoid driving to protect the catalytic converter.

Do I always need a new injector?

No. Check wiring, fuel pressure and air leaks first. Replace the injector only when tests show it is faulty.

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.