Have been a BMWCCA member since 2000 but do not frequent this forum so this is my first post. I need some help on a perplexing problem on my '94 530iT with the check engine light. This car has been well taken care of and serviced at regular intervals with 165K miles. I get around 22mpg city and almost 26mpg on highway driving. My check engine light comes on intermittently after the car has warmed up AND at highway speeds when pressure is released or reduced from the accelerator, including when I have the cruise control engaged. Once you put pressure back on the accelerator pedal or the cruise kicks in the light goes out. There are no knocks with the light on, no noticeable engine noise, no tranny noise, no other indication except the check engine light. The car runs great! I recently replaced all the seals on the tranny due to a leak; still get the light. I had the intake valve gaskets replaced and still get the light. The diagnostic test only shows codes that are coming up as miscellaneous or nuisance codes. The system is reset and then the light comes back on again. I would appreciate any ideas or suggestions. It's a great car but I need to sell it soon and must fix this problem. Thanks!
OBD1 check engine lights are self clearing, so you need to capture the code when the light is on. Any good shop should know that and should drive the car with a scanner hooked up until the light comes on to check the code. It is obviously not a huge problem or it would stay on, but that is the only way to see what is going on.
Actually, I don't think so. IIRC, there are only 4 codes that a 535i will give you for the CEL. I think OBD1 was only on the M50 and M60 and maybe the M42 in the E36 (in the US) before 95 and that they didn't change the computers from the older motors until they had to.
