Audi RS6 4.2T Oxygen Sensors & Replacement Parts

A common source of check engine lights is a failed or failing oxygen sensor. When the O2 sensor can't register oxygen content before and after your catalytic converter, it doesn't know what to do with the fuel mixture and will default to run rich. Replace old failing oxygen sensors with OEM O2 sensors or quality aftermarket O2 sensors if you're looking to save a few bucks.