This P0422 code refers to catalytic converter (cat) below the threshold rating or to make it short, is inefficient which means the cat is worn. Common symptoms for Hyundai vehicles are hesitation, pinging, cutting off and sometimes lost of power. The quickest way to test this is to check the mass sensor which can be either serviced and re-tested and look for signs of improvement or disconnecting the mass sensor and see if there is an improvement in the performance.

If the above quick tests do not work, you can do inspections like measuring the vacuum reading at 2500 rpm and see that if the reading suddenly drop to zero and stay there. Normally, it should drop slightly but it should go up 2-3 inches using a vacuum gage. Another method to use is to measure the voltage signal of the oxygen sensor after the cat. This sensor monitors the cat performance and if there is an issue with the cat, the voltage reading will oscillate wildly instead with of a small oscillation.

Another way to test this P0422 code on Hyundai vehicle is to take out the oxygen sensor at the affected exhaust manifold located near the engine cylinder head. When removed, it will make your cat breathe and it can be verified by road test. If the performance suddenly improves, it shows the cat is really plugged. If you are up to it, you can also raise the back end of the vehicle so you can go underneath the vehicle and tap the cat with a rubber mallet. A defective cat will show loose stuff inside which shows the cat content is already deteriorated.

Thanks!

This entry was posted on Tuesday, March 25th, 2008 at 5:09 am and is filed under Check Engine Light FIXES. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.