OBD Codes
Your OBD-II Trouble Codes Repair Site

P0431 Warm Up Catalyst Efficiency

Technical Description

Warm Up Catalyst Efficiency Below Threshold (Bank 2)

What does that mean?

This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. Although generic, the specific repair steps may vary depending on make/model.

Basically this means that the oxygen sensor downstream of the catalytic converter on bank 2 is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

Symptoms

You will likely not notice any drivability problems, although there may be symptoms such as a rough/hard idle when cold.

Causes

A code P0431 may mean that one or more of the following has happened:

Possible Solutions

Inspect for exhaust leaks. Next step is to measure the voltage at the oxygen sensor on Bank 2. In fact, it would be a good idea to test each oxygen O2 sensor while you're at it.

One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.

Related P0431 DTC Discussions

Need more help with a p0431 code?

If you still need help regarding the P0431 trouble code, please post your question in our FREE car repair forums.

NOTE: This information is presented for information purposes only. It is not intended as repair advice and we are not responsible for any actions you take on any vehicle. All information on this site is copyright protected. If you want to share this article or information with others, please link to this page, don't copy and paste it elsewhere.