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P2572 OBD-II Trouble Code: Direct Ozone Reduction Catalyst Deterioration Sensor Circuit 4

Check Engine Light

What the P2572 code means?

P2572 is an OBD-II generic code for the engine control module (ECM) detecting the ozone reduction catalyst has deteriorated or the sensor has failed. Some problems may be from a defective regeneration system on diesel engines.

What causes the P2572 code?

  • The ECM monitors the catalyst with sensors that measure the operation of the catalyst. When the catalyst sensor detects the catalyst, it will fall below specified limits for ozone reduction then it will turn on the Check Engine light and set the code P2572.

  • The catalyst is not operating correctly or the substrate inside it is contaminated or broken, allowing uncleaned exhaust to pass through it.

  • The catalyst sensor is not working to detect O2 levels and causing the failure.

What are the symptoms of the P2572 code?

  • The Check Engine light will be illuminated and the code is set in ECM memory as a fault. The light will stay on unless the problem goes away for at least 3 engine key cycles.

  • The vehicle may have reduced power due to the ECM failure strategy.

  • The vehicle may have rattling in the exhaust if the catalyst is broken apart.

  • The catalyst may glow red hot if the catalyst is plugged or partly melted.

How does a mechanic diagnose the P2572 code?

  • Scans for codes and documents the code in the ECM and looks at the freeze frame data for the problem before clearing the codes and retesting.

  • Runs the regeneration of the catalyst on diesel engines than have this option.

  • Checks all the O2 sensors for correct readings and notes any problems to be diagnosed.

  • Checks the exhaust for broken catalysts or O2 sensor wires burned.

  • Removes the catalyst sensor and looks for contaminations from a bad catalyst.

  • Checks the connector and wiring for corrosion causing an open or short in the sensor circuit.

Common mistakes when diagnosing the P2572 code

  • Clearing ECM memory codes before checking the freeze frame data for the main failure problem, so the failure may be duplicated and repaired

  • Failing to clear the ECM codes after the codes are fixed

  • Failing to run the regeneration for diesel engines before condemning the catalyst

How serious is the P2572 code?

Code P2572 is an indication that the ECM has got sensor signals that the catalyst is not cleaning the exhaust before it leaves the exhaust. This will fail an emission test.

What repairs can fix the P2572 code?

  • Run the regeneration to clean the catalyst in most newer diesel engines.
  • Repair the catalyst sensor connector pins for corrosion, melted or loose connections.
  • Replace the O2 sensor behind the catalyst.
  • Replace the catalyst and sensor.

Additional comments for consideration regarding the P2572 code

Code P2572 is for the catalyst sensor for some diesel engines and the code can be due to the regeneration of the exhaust and has not run or the system has problems that need fixing for it. The regeneration system cleans soot from the exhaust catalyst and allows it to work cleaning the exhaust of ozone pollutants again.

Need help with a P2572 code?

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