Coolant Heater A Internal Control Module Performance
The internal control module of coolant heater A reports a performance fault. Internal self-tests fail.
Affected components
- Coolant heater a
- Coolant heater a control module
Common causes
- High likelihood: Internal module fault
- Medium likelihood: Firmware corruption
- Low likelihood: Module software outdated, reflash may resolve
Possible symptoms
- Check engine light on
- Possible limp mode or no-start
- Multiple follow-up faults across modules
- Reset/relearn may be needed after repair
Diagnostic notes
- The malfunction indicator lamp may illuminate
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.