Direct Ozone Reduction Catalyst Efficiency Below Threshold
The DOR catalyst no longer reduces tropospheric ozone with the required efficiency, based on the deterioration sensor and operating-time model. Coating worn off the radiator surface, contaminated by road salt and grime, or thermally aged after many heat cycles. Replacing the affected radiator/coating restores function.
Affected components
- Dor catalyst
Common causes
- High likelihood: DOR coating worn off the radiator
- Medium likelihood: Coating contaminated by salt and grime
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.