528e OBC Problems

[budmur]

I have an '88 528e with an interesting problem. All of the functions of the OBC and instrument cluster seem to work perfectly, except for:

• Average MPG (Always reads 99 MPG), and
  
  Distance to Empty (Reads +620 or 620, depending on the amount of fuel in the tank.)

Does anyone have any ideas of what the problem might be?

[CraigD]

I had a similar problem a few years back. It was either a wiring problem, that is the blue and white connections (single or two wire connections not the multi wire connections) on the back of the instrument cluster were reversed or the SI board was damaged. I know the SI board was damaged on this car and that I repaired it but I can't remember for sure if that fixed it or putting the wires back on the correct connections fixed it.

There was also a problem with the CC that was related to the blue and white connectors. Multiple problems and time are making it hard for me to remember the cure.

Craig