Catalyst Heater Control Module Performance
The ECM detects that the catalyst heater control module does not respond to commands within the expected window. Heating output is reduced or absent during catalyst light-off.
Affected components
- Catalyst heater module
- Catalyst heater element
Common causes
- High likelihood: Internal control module fault
- Medium likelihood: Communication with ECM degraded
- Low likelihood: Module software outdated, reflash may resolve
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
- A drive cycle may be required after repair
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.