Hi,I had a similar problem, fixed it by cleaning the wiring connector on the back of the obc itself. i'd try that first as its easy, and doesnt cost. let me know how it goes. craig 88 735i I'm having some problems with the OBC on my '88 735i, the average speed reads only 1.7mph and the average fuel cons around 7mpg. The range seems to read ok though. Any ideas ? Cheers, Mike.