Fuel and air

P02C8 — Cylinder 12 Injector Restricted Flow

Severity: medium Drive with care, to a shop

What P02C8 means

P02C8 means the engine control module sees less fuel delivered by the cylinder 12 injector than it commanded, usually because the injector is clogged or not opening fully. The ECM judges this from mixture feedback and cylinder behavior compared with expected values. The code applies to engines with at least 12 cylinders.

Symptoms

  • Check Engine light on
  • Rough idle
  • Weak acceleration and reduced power
  • Higher fuel consumption
  • Misfires or engine hesitation
  • Unstable RPM while warming up

Possible causes

  1. Clogged fuel injector on cylinder 12
  2. Injector electrical circuit fault (open or short)
  3. Damaged wiring or poor connector contact
  4. Low fuel pressure or supply problem
  5. Air leak causing a lean mixture
  6. Faulty oxygen or air-fuel sensor giving false feedback
  7. Rarely, ECM software or hardware fault

How to diagnose

  1. Scan all codes and freeze frame data, noting any misfire or fuel trim codes
  2. Check short-term and long-term fuel trims on the bank with cylinder 12
  3. Test fuel rail pressure against specification
  4. Inspect the injector 12 connector and harness for damage, corrosion and ground issues
  5. Measure injector coil resistance and check the drive signal with a scope or noid light
  6. Compare cylinder contribution and run an injector cut-out test
  7. Check the intake system and vacuum hoses for leaks
  8. If needed, remove the injector and bench test spray pattern and flow

Common fixes

  • Professionally clean or replace the injector
  • Repair the injector wiring or connector
  • Replace the fuel filter and fix any fuel pressure problem
  • Repair intake or vacuum leaks
  • Replace a confirmed faulty oxygen sensor
  • Update software or replace the ECM only after everything else is ruled out

Questions and answers

What does P02C8 mean?

It means the cylinder 12 injector is delivering restricted fuel flow. The ECM sees that this cylinder is getting less fuel than it should.

Can I drive with P02C8?

Only briefly and gently, on the way to a shop. A lean cylinder can overheat and harm the catalytic converter, so don't put the repair off.

Will fuel injector cleaner fix it?

If the cause is light deposit buildup, a cleaner may help. Still, rule out wiring faults, low fuel pressure and air leaks 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.