13 button OBC issues

[BMWManiac]

I have a '91 325i.

I am converting to a 13 button OBC. I have the harness and the 13 button OBC itself.

Issues:
The odometer buttons don't light up. I've replaced the bulb in the back (light bar is not the issue, it works) but the buttons will still not light up? Could it be the bulb holder itself or is the computer itself bad?

Also, I get the "PPPP" with the computer on everything but time/date etc...

1) Removed and reinserted the #21 fuse....didn't do anything? The fuse wasn't blown, but when I google'd it said "replace."
2) Removed the OBC from the green plug for over 24 hours....didn't do anything.
3) Undid my battery right now. Will wait 24 hours and see if it works.

If not, could the computer itself be bad? Does it need a coding plug for a '91 325i? I bought it from a 87/88 325i.

Thoughts?

[BMWManiac]

I also tried pressing "code" and the reset button. The "mph" flashed and made no difference......still "PPPP"

New coding plug? Anything else possible to try?

[BMWManiac]

Lastly.....my coding plug ends in 793 and not 941. 793 was up to '87.....could this really matter?

[BMWManiac]

Replaced the OBC with another one and it works fine. So, the whole unit may be bad if you get "PPPP." If non of the tricks work, replace it.

[Plastic Emperor]

Yeah "PPPP" means its done

[BMWManiac]

All right.....so, I swapped in a euro cluster, and the coding plug on that was different than on my original cluster. The coding plug came from a '88 325is. When I installed it, my 13 button OBC and ALL of it's functions now work.....awesome!

So, in conclusion, try different OBCs, different coding plugs until you get ones that work together.