Working with catalytic converter Hyundai code, it deals primarily with catalytic (cat) converter failure attributed to exhaust flow restrictions. Common fault code for this is P0422 which indicates that the cat exhaust flow has gone below efficiency rating. Common symptoms for this Hyundai cat failure code 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 removed, cleaned and installed again. Any change in engine performance during a road test indicates the mass sensor is faulty.

Note: On some catalytic converter Hyundai code test, you can disconnect the mass sensor wiring terminals and watch if the engine performance change during road test. If confirmed, this shows the P0422 code is caused by a defective mass sensor not the catalytic converter. (the same method of solving this problem by disconnecting the mass sensor wiring is also applicable to GM engines).

If the above quick test does not work, you can measure the exhaust back pressure reading at 2500 rpm and see that if the reading suddenly drop to zero and stay there. Normally, it should go up slightly but it should not exceed 2-3 psi using a vacuum gage. This vacuum gage can be hooked up on the cat oxygen sensor hole so the exhaust back pressure can be measured accurately. Another method to use is to measure the voltage signal of the same 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 degree of oscillation. Change in oscillation readings should be compared with the upstream oxygen sensor to verify the changes.

Another way to test catalytic converter Hyundai code is to take out the oxygen sensor at the affected exhaust manifold located near the engine cylinder head. When removed, it will make your engine breathe and it can be verified again by a 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 internal content is already deteriorated.