OBC displaying PPPP, tried all the usual steps

[dannyzabolotny]

Hey all,

I’ve been trying to track down this annoying OBC issue and I’ve hit a bit of a dead end so I was hoping somebody might be able to point me in the right direction.

My car is a 1992 (late 91 build) 525i/5. When I bought it, the OBC just said PPPP and did not work. Here’s what I’ve tried so far to troubleshoot the issue:

- Replaced the gauge cluster with one from a 1995 525i that was known to be working. Swapped the coding plug over from the 92 cluster to maintain the correct mileage. No change.

- Replaced the OBC with the one from the 1995 525i. Worked fine in the 95 car but no change in this car, still says PPPP.

- Replaced the Check Control Module with one from the 95 car, no change. Still get a warning for my brake pads (sensor wasn’t replaced by previous owner when doing the brake job).

- Checked all of the fuses in the car, everything is good there. There are no other electrical issues and the car runs fine.

- Disconnected the battery for an hour, no difference. Removed the fuse for OBC and left it out for an hour, no change.

Currently the cluster display shows all the usual warnings and then says “Check control, see owner’s manual.” OBC flickers when you press the S/R button, but otherwise no change. Holding the S/R button for 10/20 seconds does nothing either.

Clearly the OBC is getting power since the display comes on and has backlighting on all the buttons, but perhaps there is a communication wire that has been disturbed or shorted?

I would appreciate any thoughts or suggestions y’all might have, thanks!

[Fresco34]

I would test all the pins in the back to make sure you are getting correct voltages, if you arent, then follow the wire(s) that are bad and see if there’s a split somewhere, usually near a grommet that has worn or come out causing the wires the chaff on the metal. If they all test good then it can possibly be your ECU.


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[ross1]

scroll to the bottom of the page
http://unofficialbmw.com/repair_faqs/obc.html

[dannyzabolotny]

I would test all the pins in the back to make sure you are getting correct voltages, if you arent, then follow the wire(s) that are bad and see if there’s a split somewhere, usually near a grommet that has worn or come out causing the wires the chaff on the metal. If they all test good then it can possibly be your ECU.

Do you know what the voltages should be in each pin, or do you have a diagram to reference? This will probably be my best option to figure out what the heck is happening.

scroll to the bottom of the page
http://unofficialbmw.com/repair_faqs/obc.html

I’ve tried the removing OBC trick, I left it out of the car overnight and no change. My OBC doesn’t have a reset button or a place to use a pin to reset it, that tip might be for older units.

[sunday orie]

Hi I once had a similar issue but on an e46 320i not sure what year of manufacture. Using INPA I went thru the KOMBI and there was under the “activations” there is a “software reset” option. For me that was what brought sanity back to the cluster and the PPPP. Just a suggestion if you can also try


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[fo3]

Mine shows PPPP after a battery disconnect

Have you tried setting a date? Or holding down s/r for 20 sec?
I did a search and found this thread with those and other ideas like mentioning a fuse https://www.bimmerforums.com/forum/s...P-OBC-Question

And this one mentioning rear relay and steering column damage https://www.bimmerforums.com/forum/s...omputer-issues

[sugaki]

Same issue with mine, tried leaving the OBC disconnected for 24 hours, tried cleaning the connectors and check control box, looked for a broken fuse, no dice.