Fuel and air

P02C2 — Cylinder 11 Fuel Trim at Maximum Limit

Severity: medium Drive with care, to a shop

What P02C2 means

The engine control module continually adjusts fuel delivery for each cylinder using oxygen sensor feedback. P02C2 sets when the correction for cylinder 11 reaches its maximum allowed limit and the mixture still can't be balanced. The cylinder stays too lean or too rich. This code applies only to engines with many cylinders, such as V8, V10 or V12 designs.

Symptoms

  • Check Engine light on
  • Rough idle or engine vibration
  • Reduced power and acceleration
  • Possible misfires
  • Worse fuel economy
  • Hesitation when accelerating

Possible causes

  1. Clogged or faulty fuel injector on cylinder 11
  2. Vacuum or intake air leak near cylinder 11
  3. Faulty oxygen sensor giving bad feedback
  4. Fuel delivery problem: pump, regulator or low pressure
  5. Damaged wiring or poor connector contact at the injector
  6. Ignition or mechanical fault in the cylinder (compression)

How to diagnose

  1. Scan all codes and freeze frame data, and note any other mixture or misfire codes
  2. Review short-term and long-term fuel trims at idle and under load
  3. Inspect intake ducts, hoses and gaskets for air leaks, using a smoke machine if needed
  4. Test fuel pressure against the manufacturer's spec
  5. Check the cylinder 11 injector circuit: connector, wiring, power, ground and control signal
  6. Compare cylinder balance, or swap the injector with a neighbor and see whether the fault follows
  7. Inspect the spark plug and coil for that cylinder
  8. Evaluate oxygen sensor operation and, if needed, run a compression test

Common fixes

  • Clean or replace the cylinder 11 fuel injector
  • Repair intake or vacuum leaks: gaskets, ducts, hoses
  • Replace a faulty oxygen sensor
  • Repair the fuel delivery system: pump, regulator, filter
  • Repair the injector wiring or connector
  • Fix a mechanical engine problem if low compression is confirmed

Questions and answers

What does P02C2 mean?

The ECM has used up all its fuel trim correction for cylinder 11. The mixture there is too lean or too rich and can't be compensated any further. Typical causes are the injector, an air leak or a fuel supply problem.

Can I drive with P02C2?

Briefly and carefully, for example to reach a shop. If the engine shakes badly or the check engine light flashes, stop driving to protect the catalytic converter.

What should I check first?

Start with the fuel trim data, then inspect the intake for air leaks, and test the cylinder 11 injector and fuel pressure.

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.