What it means
The module detects that the direct ozone reduction catalyst temperature sensor reading is outside its expected range or does not respond as expected. It sets the code when the reading fails the calibrated range or performance checks.
How it works
The direct ozone reduction catalyst temperature sensor reports the catalyst's temperature so the control module can assess the emissions system. This range/performance code sets when the reading is electrically plausible but falls outside the calibrated range or changes in a way the module does not expect, which can reflect a sensor problem or an abnormal catalyst temperature.
Common causes
Most likely first.
- Faulty catalyst temperature sensor
- Damaged wiring or connector
- Exhaust leak or abnormal catalyst temperature
- Sensor installation issue
- Control module fault
Symptoms
- Check engine light
- Emissions warning
- Reduced engine power
- Possible failed emissions test
How to diagnose it
- Review freeze-frame data and compare the sensor reading with other temperature readings from a cold start through warm-up to identify an implausible value or response.
- Inspect the direct ozone reduction catalyst sensor's installation, connector, and exhaust-area wiring for looseness, heat damage, corrosion, or poor seating.
- Check for exhaust leaks near the catalyst that could alter its temperature or the sensor's measurement.
- Test the sensor signal and its power or reference and ground circuits against the manufacturer's specification.
- If the sensor and circuits pass, investigate catalyst temperature and control-module inputs using the vehicle's diagnostic procedure.
Common fixes
- Correct a loose or improperly seated catalyst temperature sensor.
- Repair heat-damaged wiring or corroded connector terminals.
- Repair an exhaust leak near the direct ozone reduction catalyst.
- Replace the temperature sensor if its reading or response is outside specification.
- Address an abnormal catalyst-temperature cause identified by testing.
Can I keep driving?
If there are no drivability problems, limit driving to what is needed to arrange diagnosis; the fault may impair emissions control and cause an emissions-test failure. Stop driving if power drops substantially or the exhaust system shows signs of overheating.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.