EVAP System Monitoring Processor Performance
The dedicated EVAP monitoring processor (often a small auxiliary CPU inside the engine controller or a separate module) does not pass its self-test or runs out of step with the main monitor logic.
Affected components
- Evap monitor processor
- Control module
Common causes
- High likelihood: Internal fault in the monitoring processor
- Medium likelihood: Software memory corruption
- Low likelihood: Module software outdated, reflash may resolve
Possible symptoms
- Check engine light on
- Possible smell of fuel near tank or engine bay
- Failed emissions inspection
- Loose-cap warning may appear
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
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.