Cylinder 1 Contribution/Balance Fault
The ECU compares each cylinder's contribution to crankshaft speed (rough run analysis) and determined cylinder 1 contributes less or more than the average. This points to a mechanical or fuel delivery problem rather than a pure ignition fault.
Affected components
- Fuel injector
- Cylinder compression
- Intake valve
Common causes
- High likelihood: Injector clogged or worn
- Medium likelihood: Low compression on cylinder
- Low likelihood: Localized intake leak
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.