P03C6 — Cylinder 5 Combustion Performance

P03C6: Reports a combustion-performance fault for cylinder 5.

Meaning, symptoms, causes and checks

Reports a combustion-performance fault for cylinder 5. The definition does not select a specific ignition, injection or mechanical defect.

Affected system: Powertrain

Symptoms

  • Warning light may illuminate
  • Related system function may be impaired
  • Vehicle-specific symptoms vary

Possible causes

  • Mechanical timing or operating issue, sensor or actuator fault, connector or wiring damage
  • Related wiring, connector, power or ground fault
  • Vehicle-specific mechanical or control issue

What to check

  • Record stored and pending codes and freeze-frame data
  • Record freeze-frame conditions; compare relevant live data and inspect mechanical operation, wiring and related fault codes before replacing parts.
  • Confirm measured values against the vehicle service information
  • Retest under the conditions that set the code
  • Record freeze-frame conditions; compare relevant live data and inspect mechanical operation, wiring and related fault codes before replacing parts.
  • Repair the verified cause and confirm the code does not return

Also written as: P03C6-00, P03C600, PO3C6 (some scan tools add the fault-type byte, e.g. -00).