Catalyst Heater Circuit Performance Bank 1
The catalyst heater on bank 1 is electrically intact but does not deliver the expected thermal effect - measured catalyst light-off time is longer than calibrated. Heater element ageing, increased contact resistance, or a partial winding failure are typical causes.
Affected components
- Electric catalyst heater b1
Common causes
- High likelihood: Heater element aged - reduced power output
- Medium likelihood: Increased contact resistance in supply
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
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.