|
P0420 means either the catalytic converter isn't doing its job properly or the post cat o2 sensor isn't reading the gases properly. The post cat o2 sensors are only used for monitoring and not engine tuning like the pre cat o2 sensors so it will not harm the engine or cause driveability issues. Only issues would be emission testing if applicable or worst case the cat could break apart inside and plug up the exhaust which you would notice with possible misfires on one bank or a drastic power reduction under load. Most post cat o2 sensors will set a code if the sensor doesn't change enough and if the sensor changes to much it will set the p0420 code depending on which bank.
|