Direct Ozone Reduction Catalyst Temperature Sensor Circuit High
The DOR catalyst temperature sensor reads stuck high — short to reference voltage or open signal return. Without a valid temperature the ECM cannot enable the DOR efficiency monitor.
Affected components
- Dor temperature sensor
- Sensor wiring
Common causes
- High likelihood: Signal wire shorted to reference voltage
- Medium likelihood: Open signal return
- Low likelihood: Connector pins corroded - high contact resistance
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.