I'm not an expert. 96 and later cars require 2 sensors. 1 before the cat, 1 after. The 1st sends a signal to the ECU to make adjustments in the mixture. The 2nd looks at the exhaust after the cat and decides if the Cat is doing its job. If not it turns the light on. I think it is possible for the 1st to turn the light on also. I have seen folks run post cat simulators, I don't know how well they work out. Generally speaking BMWs and a few other cars don't like generic cats, many that work on these cars will not install non-OEM converters. I've simplified something the people send their life trying to understand.
Warren |