P2571: Direct Ozone Reduction Catalyst Temperature Sensor Circuit Intermittent/Erratic
What to do
Nothing to feel, and no mechanical concern. If it seems to relate to the weather, say so — a connector letting water in at the front of the car produces exactly this, appearing when it is wet and clearing when it dries, and that points straight at the plug rather than the sensor. Otherwise the wiring where it is clipped to the radiator is the place to look, since the radiator moves on its mountings and eventually chafes what is attached to it.
What this code means
The ozone catalyst temperature reading drops out or jumps rather than changing smoothly, and recovers.
Given where the sensor lives, the two explanations that dominate are both environmental rather than electronic. Water is the first: the connector sits low and forward, in the path of everything the front wheels throw up, and a plug whose seal has aged lets moisture in that bridges the terminals when it is wet and dries out when it is not — producing a fault that appears in the rain and vanishes in a dry spell.
Vibration is the second. A loom clipped to a radiator that moves on its mountings will eventually chafe or fatigue a conductor, and the resulting break makes and unmakes contact with the road surface.
Neither has any effect on how the vehicle drives. As with the rest of this family, the consequence is an emissions monitor that cannot complete.
Likely causes
Start here
- Water ingress into connector · easy
- Intermittent wiring fault · moderate
- Corroded or loose connector · easy
Less common
- Faulty ozone reduction catalyst temperature sensor · moderate
- Physical damage from road debris · moderate
Symptoms
Components involved
Information, not instruction
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Community experience
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