P2575: Direct Ozone Reduction Catalyst Deterioration Sensor Circuit High

P2575 reports a deterioration-sensor signal above the valid range on a direct ozone reduction (DOR) catalyst - typical for an open circuit, a missing ground or a short to a supply voltage. No vehicle maker has published how it uses P2575, and no service bulletin naming it turned up in the NHTSA index. As an analogy, VW's 2014 CC book sends an open LIN line or a short to battery from the DOR radiator sensor to P2570. Because the DOR coating sits on the radiator, a radiator swap is the most likely moment for a connector to be left off or a wire to be damaged. P2574 covers the low side, P2576 brief dropouts. The engine runs normally; only emissions monitoring is affected.

Medium severity. Can I keep driving?You can usually keep driving, unless you notice a loss of power, which may point to a blockage. The car may not pass an emissions inspection.

Symptoms

Check engine light on
No change in power or engine temperature

Most likely causes

Connector left off or damaged during radiator work
Broken signal or ground wire
Signal wire shorted to a supply voltage

What to check, in order

Start with the simplest. You can tick off each step.

First resolve any misfire or fuel mixture codes
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Look for exhaust leaks between the engine and the second sensor
Use live data to compare the signals from both oxygen sensors
Check for a blockage by measuring exhaust back pressure
Replace the catalytic converter only at the end of the diagnosis

Good to know

Repair difficulty: medium
It affects emissions.

What each character of P2575 means

P: Powertrain: engine and transmission
2: Generic code: same on every make
5: Speed and idle
75: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2575?

You can usually keep driving, unless you notice a loss of power, which may point to a blockage. The car may not pass an emissions inspection.

What causes code P2575?

The most common causes are: connector left off or damaged during radiator work; broken signal or ground wire; signal wire shorted to a supply voltage.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.