OBD-II code · Powertrain (generic, extended)
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.
Is it safe to drive with P2577?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyDOR coating worn off the radiator
- PossibleCoating contaminated by salt and grime
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1.5–4 h
- Emissions test
- Likely to fail
- Parts involved
- Dor Catalyst
Related codes
- P2574Direct Ozone Reduction Catalyst Deterioration Sensor Circuit Low
- P2575Direct Ozone Reduction Catalyst Deterioration Sensor Circuit High
- P2576Direct Ozone Reduction Catalyst Deterioration Sensor Circuit Intermittent/Erratic
- P2578Turbocharger/Supercharger Speed Sensor A Circuit
- P2579Turbocharger/Supercharger Speed Sensor A Circuit Range/Performance
- P257AVacuum Reservoir Control Circuit/Open
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.