88 735iL - Jumpy speedometer, owners handbook question

My 1988 735il has a jumpy speedometer, does anybody have any ideas? Also, how does it know that the owners manual is not there? Is it magnetic or does it have a microswitch. I don't know where it's supposed to be kept. Thanks

The speed sensor is in the differential. It is on the back side and most likely needs to be taken out and cleaned. It acts like a magnetic plug and picks up all of the fine metal wear bits in the differential.

Thanks Terry, Should I have a plastic plug ready when I pull the sensor, does the differential oil come out when you take out the sensor? Anyway, thanks a ton, I'll be under there today.

Oil level should be at the bottom of the fill plug which should be lower than the sensor.

Thanks a million Terry, happy touring. Any ideas on the owners handbook message on the error board?

I think it is telling you to look up the meaning of an error in the handbook. Is there a message before the handbook one?

I changed the brake pads and the sensors were shot. I ordered some new ones but haven't put them on. that's the only other message. brake linings and owners handbook. I'll put those sensors on today as well, and post how it went. Thanks again.

Adolfo

Well, you were absolutely right, both the brake linings and the owners handbook are now gone and there's nothing there but a nice black area. When I push the button, I get a cool empty marquee. thanks.
However, on the speedometer sensor, ugh ugh ugh. I jacked up the car all the way and got under there. brushed all the grime and got ready to remove it, but the crossmembers and the area is so restricted, I couldn't even get a wrench in there. The bottom bolt is somewhat accessible but the top one is impossible. I gave up after a couple of hours. I'll do some research on it. I bet you the gas tank has to be removed or the differential dropped. Else, $1000 bucks at the stealership ; )