Fuel and air

P02F5 — Cylinder 8 Injector Circuit Range/Performance

Severity: medium Drive with care, to a shop

What P02F5 means

The engine control module fires each fuel injector by switching its circuit to ground for a precise time, and it monitors the current and voltage in that circuit. P02F5 sets when the cylinder 8 injector circuit falls outside the expected range or the injector does not respond as commanded. The cause may be the injector itself, its wiring, or the driver inside the ECM.

Symptoms

  • Check Engine light on
  • Rough or uneven idle
  • Loss of power or hesitation
  • Worse fuel economy
  • Misfire on cylinder 8
  • Smell of unburned fuel

Possible causes

  1. Failed or sticking cylinder 8 injector
  2. Open or short in the injector wiring harness
  3. Corroded or loose injector connector
  4. Clogged injector from deposits
  5. Faulty injector driver inside the ECM
  6. Low or unstable fuel pressure
  7. Air leak skewing the air-fuel mixture

How to diagnose

  1. Scan all codes and freeze-frame data, and note any misfire codes
  2. Inspect the cylinder 8 injector harness and connector for damage, oil and corrosion
  3. Review fuel trims and mixture adaptation at idle and under load
  4. Measure injector coil resistance and compare it with specs and the neighboring injectors
  5. Check the control signal at the connector with a noid light or scope
  6. Test fuel pressure and how well it holds after shutdown
  7. Compare cylinder balance with a scan tool, and swap injectors if needed to see if the fault follows
  8. Check the intake system for vacuum leaks

Common fixes

  • Replace the faulty injector
  • Repair the wiring or replace the damaged connector
  • Clean the injector on a bench if it is clogged
  • Fix fuel pressure problems (pump, filter, regulator)
  • Repair or replace the ECM if the driver fault is confirmed

Questions and answers

What does P02F5 mean?

It is a generic code saying the ECM sees the cylinder 8 injector circuit operating outside its expected range. The injector or its wiring is the most common culprit.

Can I drive with P02F5?

Only a short distance, carefully, to a repair shop. Driving long with a misfire can damage the catalytic converter.

Will an injector cleaner fix P02F5?

Only if the cause is a clogged injector. Check the wiring, connector and injector electrical values first, or the cleaner will not help.

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.