Camiman

Hi this is my first time posting so please bare with me. I have a Euro spec 1991 928 s4 that has a intermittent odometer problem. The speedo seems to work fine and so does the tripometer it's just the odometer that stops working lately after a few kms. I guess that I didn't mention the fact that this model has a digital odometer ,so what I would like to know is if it is a sending unit problem where is it located because I've gotten mixed answers when I ask people if its on the transmission or at one of the ABS sensors at the wheels? Sure would like to resolve this !! Thanks Bob

FLYVMO

For that model year it should be the front ABS sensor, and the CEB (relay board) should have a relay that converts the ABS pulse and send that to the speedometer. I would think that the mileage computation is done in the instrument cluster and not in that relay so if you have a valid speedometer signal and speed indication, then you may have a instrument cluster issue. Perhaps someone with more experience with it can chime in.

Cheers!
Carl

ROG100

That is a new issue I have not come across before in a digital cluster. It may be very simple in that the connection of the harness to the CB need cleaning. If everything else is working that would be my sort of educated guess. Remove the cluster and clean all the connections to the circuit board (four of them) with an eraser.

Camiman

Hey Carl,which front wheel abs sensor do you think produces the pulse for the odometer?

Thanks again Bob

ROG100

Left Front - however if that was the issue you would have no speed signal either.
Well worth your time to remove all the sensors at each wheel, clean and replace. Also clean each ground from the sensor to the hub.

Camiman

Thanks for the advise , will check the relay this weekend and get back to you if it works.