Fuel and air

P02D8 — Cylinder 7 Injector Offset Learning at Minimum Limit

Severity: medium Drive with care, to a shop

What P02D8 means

The engine control unit fine-tunes each injector's opening time so every cylinder gets the same amount of fuel. P02D8 means the correction for the cylinder 7 injector has reached the lower end of its learning range and cannot go any lower. This usually points to that injector delivering more fuel than expected, or another fault skewing the mixture in that cylinder.

Symptoms

  • Check Engine light on
  • Rough idle
  • Hesitation or stumbling under acceleration
  • Reduced power
  • Worse fuel economy
  • Possible cylinder 7 misfire
  • Fuel smell from the exhaust

Possible causes

  1. Leaking, sticking or carbon-fouled cylinder 7 injector
  2. Poor connection or damaged wiring at the injector connector
  3. ECU software glitch or internal fault
  4. Incorrect learned values after an injector swap or adaptation reset
  5. Fuel supply problems such as high pressure or a faulty regulator
  6. Air leak or sensor fault skewing the mixture

How to diagnose

  1. Scan all codes and freeze-frame data, noting any misfire or fuel trim codes
  2. Read per-cylinder injector correction values and fuel trims on a scan tool
  3. Inspect the cylinder 7 injector connector and wiring for corrosion or damage
  4. Measure the injector coil resistance and compare it with neighboring cylinders
  5. Test fuel rail pressure and pressure hold after shutoff
  6. Check cylinder balance and the spark plug in cylinder 7
  7. Rule out vacuum or intake leaks and faulty oxygen or airflow sensors
  8. If needed, bench test the injector or swap it with another cylinder to see if the fault follows

Common fixes

  • Clean or replace the cylinder 7 injector
  • Repair the wiring or replace the connector
  • Fix the fuel system fault (regulator, pump, filter)
  • Run the injector learning procedure after replacement, then update or replace the ECU only if it is confirmed faulty

Questions and answers

What does P02D8 mean?

The ECU has reduced the cylinder 7 injector correction to its minimum allowed value. Most often the injector is delivering too much fuel or its circuit has a problem.

Can I drive with P02D8?

Briefly, if the engine runs smoothly. If it misfires, stop driving, since unburned fuel can damage the catalytic converter and engine.

Should I replace the injector right away?

No. Check the wiring, fuel pressure and air leaks first. Replace the injector once other causes are ruled out or it fails testing.

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.