Catalyst Heater Control Module Supply Voltage
The catalyst heater control module reports supply voltage outside the expected window. Heating output cannot be regulated as expected.
Affected components
- Catalyst heater module
- Wiring harness
Common causes
- High likelihood: Module supply fuse blown
- Medium likelihood: Alternator regulator drift
Possible symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
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.