Engine-Codes - Generic - P0431

P0431 Code - Warm Up Catalyst Efficiency Below Threshold Bank 2

- Code Popularity: 49,530 Views
- Repair Importance Level: 2/3
- Repair Difficulty Level: 2/3
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What are the Possible Causes of the DTC P0431?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Warm Up Three-Way Catalytic converter deterioration or malfunction
  • Exhaust system leaks
  • Loose front or rear HO2Ss
  • Faulty front heater O2 sensor
  • O2 sensors harness is open or shorted
  • O2 sensors poor electrical connection

Code Tech Notes

As the code description implies, the P0431 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases, the catalytic convert needs to be replaced to fix the problem. If the P0431 code is combined with other codes, try fixing the other codes first.

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How to Fix the DTC P0431?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P0431 code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

What Does the P0431 Code Mean?

The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor). A three-way catalyst converter (Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase. When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three-way catalyst malfunction is diagnosed. The P0431 code is set when the Engine Control Module (ECM) detects the rear HO2S value difference becomes closer to the value of the front HO2S. The ECM monitors when the vehicle speed is 25-60 MPH, the load is 22-45 percent, and the engine speed is 1000-3000 RPM.

P0431 Code - Warm Up Catalyst Efficiency Below Threshold Bank 2

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Code P0431 Information for Specific Makes

  • P0431 Audi Warm Up Catalyst Efficiency Below Threshold Bank 2
  • P0431 Chrysler Warm Up Catalyst Efficiency Below Threshold Bank 2
  • P0431 Dodge Warm Up Catalyst Efficiency Below Threshold Bank 2
  • P0431 Hyundai Warm Up Catalyst Efficiency Below Threshold Bank 2
  • P0431 Jeep Warm Up Catalyst Efficiency Below Threshold Bank 2
  • P0431 KIA Warm Up Catalyst Efficiency Below Threshold Bank 2  📷
  • P0431 Mazda Warm Up Catalyst System LH Efficiency Below Threshold
  • P0431 Mercedes-Benz Warm Up Catalyst Efficiency Below Threshold Bank 2
  • P0431 Mitsubishi Warm Up Catalyst Efficiency Below Threshold- Cylinders 2-3
  • P0431 RAM Warm Up Catalyst Efficiency Below Threshold Bank 2
  • P0431 Volkswagen Warm Up Catalyst Efficiency Below Threshold Bank 2

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