P2571
Direct Ozone Reduction Catalyst Temperature Sensor Circuit Intermittent/Erratic
The DOR catalyst temperature sensor signal jumps or drops out — typically loose connectors or chafed wiring near the radiator pack.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
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.
- Loose connectorCommon
- Chafed harnessPossible
- Connector with intermittent contact under vibrationLess likely
Parts involved
- Dor Temperature Sensor
- Sensor Wiring
P2571 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.