P0422 code Hyundai Accent 2001 (1500cc). "Main Catalyst Efficiency Below Threshold Bank 1".Help!

Question

P0422 code in Hyundai Accent 2001 (1500cc). "Main Catalyst Efficiency Below Threshold Bank 1". Can someone tell me how to measure the O2 sensors? or how to resolve it, please!

Answer 1

HI there,

You need a scan tool that can read the live data on the sensors. The rear O2 sensor should show a smooth wave pattern with the voltage ranging from about .2 up to 1.0 volts. Usually about every 10 seconds or so. If the voltage stays low, then it means the converter is not cleaning the exhaust and generating any O2. Most of the time with this code, the converter is the actual problem and needs to be replaced.