P2570: Direct Ozone Reduction Catalyst Temperature Sensor Circuit High

What it means

The DOR catalyst temperature sensor reads stuck high — short to reference voltage or open signal return. Without a valid temperature the ECM cannot enable the DOR efficiency monitor.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The direct ozone reduction (DOR) catalyst temperature sensor reports the temperature used by the engine control module to assess that catalyst system. P2570 sets when the sensor circuit reads higher than its allowed range, so the module cannot rely on the temperature input for its monitor.

Common causes

Most likely first.

1. Signal wire shorted to reference voltage
2. Open signal return
3. Connector pins corroded - high contact resistance

Symptoms

• Check engine light

How to diagnose it

1. Check freeze-frame data and scan-tool temperature data for the DOR catalyst sensor, and compare the reading with other temperature data when the system is cold.
2. Inspect the sensor connector and harness for corrosion, an open return path, or a signal wire touching a reference-voltage wire.
3. Check the sensor return and reference circuits for continuity or unintended connection, following the vehicle wiring diagram.
4. Measure the signal and reference circuits at the sensor and control-module connectors, comparing results with the manufacturer's specifications.
5. If wiring and connections pass, test the DOR temperature sensor and then the control-module input according to the manufacturer's procedure.

Common fixes

• Repair a signal wire shorted to the reference-voltage circuit.
• Restore an open sensor-return connection.
• Clean or repair corroded connector terminals.
• Replace the DOR catalyst temperature sensor if it fails the specified circuit test.

Can I keep driving?

The listed symptom is a check-engine light, with no stated driveability effect; normal driving is generally possible if the vehicle runs normally. The DOR efficiency monitor may not operate, so address the fault to restore monitoring.