P2574: Direct Ozone Reduction Catalyst Deterioration Sensor Circuit Low
What to do
Nothing to feel and no mechanical concern — this equipment has no effect on the engine. It matters only for emissions testing.
Ask for the wiring across the front of the vehicle to be inspected rather than the sensor simply being replaced. It runs through the area that takes road salt and grit, with earthed metal all around it, and a rubbed-through wire there is more likely than a failed sensor.
What this code means
The deterioration sensor circuit reads below its valid range — normally a short to ground, or a sensor that has failed to the bottom of its scale.
The reason a short to ground is the leading candidate here is positional rather than electrical. This wiring runs across the front of the vehicle, through the area that collects road salt, water and grit, and there is earthed metal within a few millimetres of it in almost every direction — the radiator support, the condenser brackets, the bumper reinforcement. Insulation that has been abraded or salted for a decade has no shortage of places to find a ground.
No driveability consequence. What is lost is the emissions monitor, exactly as at P2567.
Likely causes
Start here
- Wiring shorted to ground · moderate
- Faulty ozone reduction catalyst deterioration sensor · moderate
- Corroded or loose connector · easy
Less common
- Damaged wiring harness · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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