Warm Up Catalyst Efficiency Below Threshold Bank 2
Table of contents
- Possible Causes
- How To Fix
- Tech Notes
- Cost To Diagnose
- When is the code detected
- Possible Symptoms
- Description
P0431 HYUNDAI Possible Causes
- 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
How do I fix code P0431 HYUNDAI?
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’s pins.
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.
Cost of diagnosing the P0431 HYUNDAI code
The cost of diagnosing the P0431 HYUNDAI code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
When is the code detected
If the frequency ratio of front and rear HO2S is higher than threshold value, the PCM determines that a fault exists and the P0431 code is stored.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P0431 HYUNDAI Description
The catalyst’s efficiency is demonstrated by its ability to oxidize CO and hydrocarbon emissions. The Powertrain Control Module (PCM) compares the output signals of the front and rear oxygen sensors to determine whether the output of the rear sensor is beginning to match the output of the front oxygen sensor. Air/fuel mixture compensation keeps the frequency of the front oxygen sensor high due to the changes from rich-to-lean comvustio. The catalyst causes the rear oxygen sensor to have a lower frequency. As the catalyst wears, the rear oxygen sensor’s signal trace begins to match the front oxygen sensor’s signal trace. That is because the catalyst becomes saturated with oxygen and cannot use the oxygen to convert hydrocarbon and CO into H₂O and CO₂ with the same efficiency as when it was new. A completely worn catalyst shows a 100% match between the frequency of the front and rear sensors.