I just bought a used 525i with the check engine light on. The engine seems to run fine but I live in California and the car cannot be registered without passing a smog test. However, I am told it won't pass smog as long as the check engine light is on.
My question is, will the check engine light go off automatically if the problem is fixed or does the system have to be reset by some mean. I was thinking maybe changing the plugs and doing a tuneup might do the trick without having to go to the dealer.
Any advice would be welcome.