Fuel and air

P01E2 — Cylinder 12 Injection Timing Over-Advanced

Severity: medium Drive with care, to a shop

What P01E2 means

The engine control unit compares the actual start of injection in cylinder 12 with the calculated target and finds it occurring earlier than allowed. Injection timing is normally based on crankshaft and camshaft position signals, and the ECU opens the injector with a control pulse. This code applies to 12-cylinder engines or systems with extended cylinder numbering.

Symptoms

  • Check engine light on
  • Rough idle
  • Reduced power and sluggish acceleration
  • Possible misfire in cylinder 12
  • Increased fuel consumption
  • Harsh running or knocking noises

Possible causes

  1. Faulty or sticking cylinder 12 fuel injector
  2. Damaged injector wiring: open, short or corroded connector
  3. ECU fault or faulty programming
  4. Mechanical timing error, such as a stretched chain or belt or a jumped tooth
  5. Failing crankshaft or camshaft position sensor
  6. Unstable fuel pressure
  7. Air leak skewing the mixture

How to diagnose

  1. Read all codes and freeze frame data, noting any misfire or sensor codes
  2. Review fuel trims and mixture adaptation values
  3. Inspect the cylinder 12 injector connector and harness, and test power and ground circuits
  4. Scope or scan the injector control pulse
  5. Compare cylinder balance and individual cylinder contribution
  6. Measure fuel pressure against the manufacturer spec
  7. Check crank and cam sensor signals and correlation, then verify mechanical timing if needed
  8. Look for intake air leaks and exhaust leaks

Common fixes

  • Clean or replace the cylinder 12 injector once confirmed faulty
  • Repair wiring and connectors
  • Replace a failing crank or cam position sensor
  • Correct mechanical timing by replacing the chain or belt and setting the marks
  • Reflash or replace the ECU only after ruling out other causes

Questions and answers

What does P01E2 mean?

The ECU detected that injection in cylinder 12 starts too early compared with its target. The cause may be the injector, wiring, position sensors or the ECU itself.

Can I drive with P01E2?

Only briefly and gently, to reach a shop. Extended driving with over-advanced injection risks knock and cylinder damage.

Will clearing P01E2 fix it?

Clearing the code only works temporarily. If the cause remains, it will return, so check the injector, wiring and engine timing 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.