P0420Catalyst System Efficiency Below Threshold (Bank 1)

The computer compares the oxygen sensors before and after the catalytic converter on bank 1 to judge how well it is cleaning the exhaust. This code means the converter on bank 1 is no longer working efficiently enough. Most often the catalytic converter itself is worn out, but a faulty sensor or an exhaust leak can also trigger it.

Ամենատարածված պատճառներն են՝ Worn-out or failing catalytic converter (bank 1), Failed or lazy downstream O2 sensor, Exhaust leak before or near the converter or sensors, Engine running rich/lean or misfiring, damaging the converter, Aftermarket or low-quality converter that doesn't meet spec, Oil or coolant contamination of the converter։

Սովորաբար անվտանգ է կարճ տարածությունների վրա վարել, սակայն շուտով ստուգել տվեք։

You can usually keep driving short distances; this is an emissions code, not an immediate safety risk. However, have it diagnosed before replacing the costly converter, because an exhaust leak, a bad sensor, or an unresolved misfire can cause it. Fixing any upstream problem first prevents ruining a new converter.