Hi Guys. I've just retrofitted the 18 button OBC to my E36 and can't get the fuel consumption to register. I'm pretty competent with auto electrics and I've read everything I can find on the web and have studied the Bentley wiring digrams until I'm cross eyed.
My car doesnt have check control but all the wiring was there on X1070 and X16. I had to fit the wire to pin 10 of X17 and scotch-locked all the others. I've tested all the wires for continuity. I also have an E36 convertible and have swapped the OBC's over with the same result.
Logically the MPG calculation is based on amount of fuel used divided by distance. The range button does work and figure goes down so I unlocked the OBC and did test No8. It registers zero km/h when moving so it seems there isn't a signal from the speedo, even though the wiring is spot on. Any ideas?