[kik5150]

The check engine light is the ultimate Idiot light designed for one thing- make money for the dealership. It would cost $.02 more to have an LCD readout of the actual problem, but then the customer would not have to take the car back to the dealership for service.

[chrisser]

It would cost $.02 more to have an LCD readout of the actual problem, but then the customer would not have to take the car back to the dealership for service.

Most people don't know this, but Cadillac of all companies had built in diagnostics in the late 80s and early 90s. Using the HVAC panel, you could scroll through any fault codes and, on some cars, you could modify selected parameters in the programming, and even actuate various sensors and relays for testing purposes.

Was really slick and sophisticated. When the govt. mandated OBDII, Cadillac apparently decided it wasn't worth rewriting all that code to comply with the new standards and dropped it altogether.

[T-Bone Texan]

My ‘96 Ford Ranger had a Check Engine light that came on at 25,000 miles automaticaly (I ignored it), and it automatically turned off at 50,000 miles, and when it turned on again at 75,000 miles I just told the new owner that he should not have bought a Ford.