OBD Code Lookup

P0420 means the engine computer sees that the catalytic converter on bank 1 is not cleaning exhaust as efficiently as expected. The converter may be worn, but exhaust leaks, oxygen sensor problems, misfires, or fuel mixture issues can also

P0430 means the engine computer believes the catalytic converter on bank 2 is not reducing exhaust pollutants well enough. On V-style engines, bank 2 is the side that does not contain cylinder 1. The code can come from the converter itself,

P0171 means the engine computer is adding extra fuel because bank 1 is running lean. In plain terms, the engine is getting too much air, not enough fuel, or incorrect sensor information. Vacuum leaks, intake leaks, fuel delivery issues, and

P0174 means bank 2 is running lean and the computer is adding fuel to compensate. It is common on V-style engines when unmetered air enters one side of the intake, fuel delivery is weak, or the mass airflow reading is inaccurate for the act

P0300 means the engine is misfiring randomly or across multiple cylinders instead of one clearly identified cylinder. Ignition, fuel, air leaks, compression problems, or timing issues can all interrupt combustion and trigger this code.

P0301 means cylinder 1 is not burning its air-fuel mixture consistently. The problem may be isolated to that cylinder, such as a spark plug, coil, injector, compression issue, or local air leak near the intake runner.