Catalyst System Over Temperature (Bank 1)
A temperature sensor in the exhaust catalyst on bank 1 reports a value above the safe operating limit. Sustained over-temperature can sinter the precious-metal washcoat and destroy conversion efficiency.
Affected components
- Catalytic converter
- Exhaust temperature sensor
Common causes
- High likelihood: Persistent misfire dumps unburned fuel into the cat
- Medium likelihood: Sustained rich mixture from leaking injector or fuel pressure regulator
- Low likelihood: Catalyst temperature sensor drifts high
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
- Reduced-power or limp mode may occur
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.