Having a Hyundai car with the P0422 code can be a frustrating experience as it can cause your car to run erratically and lead to poor engine performance. This code is a catalyst efficiency below normal (bank 1) code and is triggered when the PCM detects that the rear HO2S-12 switch rate is similar to the front HO2S-11 switch rate for over 3 seconds. In some cases, it can be caused by air leaks at the exhaust manifold or in the exhaust pipes, or by a catalytic converter that is contaminated, damaged, or has failed. It can also be caused by an older front HO2S or one that is contaminated with fuel or moisture.
Causes and Solutions for the Hyundai P0422 Code
| Cause | Solution |
|---|---|
| Air leaks at the exhaust manifold or in the exhaust pipes | Check the exhaust system for any cracks or leaks and repair or replace any damaged parts. |
| Catalytic converter is contaminated, damaged or has failed | Replace the catalytic converter with a new one. |
| Front HO2S is older (aged) than the rear HO2S (HO2S is lazy) | Replace the front HO2S with a new one. |
| Front HO2S or rear HO2S is contaminated with fuel or moisture | Clean the HO2S with a special solvent and replace any damaged parts. |
https://www.youtube.com/watch?v=83GLIoKEpb0