Auto Parts: obd II codes, PO446, PO431

Question
hello I have hyundai gx300/2001 and the scanner give me the codes P0446 AND P0431 I want know how I can fix my car ok. thank you for your help

Answer
The PO446 code is an Evaporative Emission Control System Vent Control Circuit Malfunction.  Check the vent control valve in your emissions system for this one.

PO431 is an Warm Up Catalyst Efficiency Below Threshold (Bank 2).   The best bet for this code will be to perform a ratio test between the front and rear O2 sensors to prove if the converter is getting weak and needs to be replaced. If necessary, have them make a printout of the inversion ratio pattern as was captured by IDS under PID data monitor and will help you along in the process. A bad rear O2 is not going to throw a code P0431 so do not let them tell you otherwise.

I might be able to help further if I had more info on your vehicle, i.e., mileage & engine size.

Hope this helps!

- Brent