Fuel and air

P02C4 — Cylinder 11 Fuel Injector Restricted Flow

Severity: medium Drive with care, to a shop

What P02C4 means

The engine control module compares actual fuel delivery with what it commanded, using fuel trims and oxygen sensor feedback. P02C4 sets when the cylinder 11 injector delivers less fuel than requested, leaving that cylinder running lean. The usual culprits are a clogged injector or restricted fuel supply. This code appears on engines with many cylinders, such as V12s, where numbering reaches 11 and beyond.

Symptoms

  • Check engine light on
  • Reduced power and sluggish acceleration
  • Rough idle or misfire
  • Worse fuel economy
  • Engine shudder under load
  • Possible extra exhaust smoke

Possible causes

  1. Clogged or carbon-fouled injector on cylinder 11
  2. Damaged wiring or connector at injector 11
  3. Poor quality or contaminated fuel
  4. Low fuel pressure (weak pump, bad regulator, clogged filter)
  5. Intake air leak near that cylinder
  6. Internal electrical or mechanical injector fault
  7. Rarely, a faulty ECM

How to diagnose

  1. Scan for all codes and freeze frame data, noting any other fuel or misfire codes
  2. Review short-term and long-term fuel trims; high positive values point to a lean mixture
  3. Inspect the injector 11 connector and harness for corrosion, chafing and poor contact
  4. Measure injector resistance and compare it with other injectors and the specification
  5. Test fuel rail pressure against the specified value
  6. Check cylinder balance, or swap the injector with a neighbor to see if the fault follows it
  7. Inspect the intake system for vacuum or air leaks
  8. Check fuel quality and the condition of the fuel filter

Common fixes

  • Professionally clean or replace the cylinder 11 injector
  • Repair wiring and replace a damaged connector
  • Replace the fuel filter and drain bad fuel
  • Replace the fuel pump or pressure regulator if pressure is low
  • Fix any intake air leak

Questions and answers

What does P02C4 mean?

The ECM found that the cylinder 11 injector is delivering less fuel than commanded. The most common cause is a clogged injector or a fuel supply problem.

Can fuel injector cleaner fix P02C4?

Additive may help with light deposits, but a badly clogged injector usually needs bench cleaning or replacement. Rule out wiring faults and low fuel pressure first.

Is it safe to drive with P02C4?

Short trips may be fine, but a lean cylinder and misfires can damage the engine and catalytic converter. Don't put off the repair.

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.