P2575: Direct Ozone Reduction Catalyst Deterioration Sensor Circuit High

What it means

The DOR deterioration sensor signal voltage reads above the upper limit — short to reference voltage or open signal return.

At a glance

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

How it works

The DOR catalyst deterioration sensor reports a signal used by the engine control module to evaluate the catalyst system. P2575 sets when that signal rises above its allowed upper limit, such as when it is shorted to reference voltage or its return path is open.

Common causes

Most likely first.

1. Signal wire shorted to reference voltage
2. Connector pins corroded - high contact resistance
3. Supply wire pinched against B+ source

Symptoms

• Check engine light

How to diagnose it

1. Review freeze-frame and live data to verify that the DOR deterioration sensor signal is above its expected range.
2. Inspect the sensor connector and harness for an open return, corrosion, or a signal wire touching the reference-voltage or power circuit.
3. Check the sensor return path and connector pin condition for an open or poor connection.
4. Test the signal wire for shorts to reference voltage or battery power and compare circuit readings with the manufacturer's specifications.
5. If the circuit checks pass, test the deterioration sensor and module input for an internal fault.

Common fixes

• Repair a signal wire shorted to the reference-voltage circuit.
• Restore the open sensor-return path.
• Repair corroded terminals or damaged connector pins.
• Replace the DOR deterioration sensor if it produces an out-of-range signal with sound wiring.

Can I keep driving?

A check-engine light is the stated symptom, and no limp mode is indicated, so driving is generally possible if the vehicle behaves normally. The DOR catalyst monitor may be unavailable while the signal remains high.