Fuel and air

P02CC — Cylinder 1 Injector Offset Learning at Minimum Limit

Severity: medium Drive with care, to a shop

What P02CC means

The engine control module constantly trims how long each injector stays open so every cylinder gets the same amount of fuel. P02CC means the learned correction for cylinder 1 has reached the lowest value it is allowed to use. This usually points to an injector delivering more fuel than commanded, or a rich condition from another cause.

Symptoms

  • Check Engine light on
  • Rough idle, especially on a cold start
  • Misfire or engine shake
  • Higher fuel consumption
  • Fuel smell or black exhaust smoke
  • Reduced power and sluggish response

Possible causes

  1. Leaking or sticking-open injector on cylinder 1
  2. Damaged wiring or connector at the cylinder 1 injector
  3. Fuel pressure too high or a faulty pressure regulator
  4. ECM software or adaptation problem
  5. Another fault causing a rich mixture (sensors, fuel in the oil)
  6. Mechanical cylinder issue such as low compression

How to diagnose

  1. Read all codes and freeze frame data and note any misfire or fuel trim codes
  2. Review short and long term fuel trims and per-cylinder adaptation values
  3. Inspect the cylinder 1 injector connector and harness for corrosion, damage or loose pins
  4. Measure injector resistance and check the drive signal with a scope or noid light
  5. Check fuel pressure and whether it holds after shutdown
  6. Run a cylinder balance or injector cutout test
  7. Inspect the cylinder 1 spark plug for signs of a rich mixture
  8. Check the oil for fuel dilution

Common fixes

  • Replace or bench-clean the cylinder 1 injector
  • Repair the injector wiring or connector
  • Replace a faulty fuel pressure regulator or other fuel system part
  • Update the ECM software and reset adaptations after repair
  • Fix whatever else is causing the rich condition

Questions and answers

What does P02CC mean?

The ECM is trimming fuel from the cylinder 1 injector, but the correction has reached its minimum. Most often the injector is delivering too much fuel or the mixture is rich for another reason.

Can I drive with P02CC?

Short trips are usually possible, but don't wait long. Excess fuel can harm the catalytic converter and dilute the oil, and a misfire can damage the engine.

Is clearing the code enough?

No. If the cause remains, the code will return. After the repair, reset the adaptations and confirm the values return to normal.

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.