What it means
The module detects a fault in the direct ozone reduction catalyst temperature sensor circuit. It sets the code when the circuit response is missing or outside expected electrical operating conditions.
How it works
The direct ozone reduction catalyst temperature sensor monitors temperature at that emissions-control catalyst, and the control module uses its electrical signal to assess catalyst operation. This circuit code sets when the signal is missing or has an electrical condition outside the expected operating range; it does not by itself identify whether the sensor, wiring, supply, or ground is at fault.
Common causes
Most likely first.
- Faulty catalyst temperature sensor
- Damaged wiring or connector
- Open or short in sensor circuit
- Poor sensor ground or power
- Control module fault
Symptoms
- Check engine light
- Emissions warning
- Reduced engine power
- Possible failed emissions test
How to diagnose it
- Read the stored and pending codes and freeze-frame data, then compare the catalyst temperature reading with other temperature data when the exhaust is cold and during warm-up.
- Inspect the direct ozone reduction catalyst sensor, its connector, and nearby wiring for heat damage, corrosion, loose pins, or disconnection.
- Check the sensor's power or reference and ground circuits using the wiring diagram and the manufacturer's specification.
- Test the sensor signal circuit for an open or short and verify connector continuity while gently moving the harness.
- If the circuit tests correctly, evaluate the temperature sensor and then the control module according to the manufacturer's diagnostic procedure.
Common fixes
- Reconnect or secure a loose sensor connector and repair damaged nearby wiring.
- Clean or replace corroded connector terminals and restore a poor sensor ground.
- Repair an open or short in the sensor circuit.
- Replace the direct ozone reduction catalyst temperature sensor if it fails the specified tests.
- Repair or replace the control module only if its circuit checks fail to identify another cause.
Can I keep driving?
If the engine runs normally, a short, gentle drive is generally possible, but emissions monitoring may be impaired and the vehicle could fail an emissions test. Arrange diagnosis soon, especially if reduced power or an emissions warning appears.
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.