Does the shop retain right of first refusal, or is moonlighting A-OK?

Diagnosing a catalytic converter isn’t always the most straightforward process simply because it’s so far downstream from other parts that affect its operation. You might watch this video and say, “Of course!”, but not every technician has been given the proper education on what else a converter efficiency code just might mean. Take a look as Nick and Lemmy share some of there tips for hashing out what might be causing that P0420.