P2577
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.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Common causes
Ordered by how often each turns out to be the cause.
- DOR coating worn off the radiatorCommon
- Coating contaminated by salt and grimePossible
Parts involved
- Dor Catalyst
P2577 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.