Diagnostice computer not able to communicate with car

U

Unclepip

Member
I recently took my 2003 E85 into BMW as there were a number of seeming unrelated problems i.e. Roof not operating, windows not operating, radio displaying "DISABLED", indicator tell tale not operating on dash.
I was advised, after spending £138, that their diagnostic computer was not able to communicate with the car - there was a suggestion that the "car body computer" may be at fault and until that is proven/resolved they would not be able to diagnose any of the other problems further.

Can anybody advise, where to find the "car body computer" - is it the GM5 module behind the glove box? Does this unit control the affected functions described above?

Any help in advising where to start with this problem is much appreciated, I have just purchased a diagnostic tool form a fellow member, so am hoping that will help if I can get over this first hurdle.

Thanks

Phil
 
the GM5 is the "car body computer".

But all those things relate to the I/K Bus being down.
Radio doesn't talk to GM5, so if the GM5 was dead, the radio would still work.
It saying DISABLED happens when you disconnect it from the IBUS.

I've had a RADIO sat on my conservatory desk for a few days now, using a IBUS simulator circuit that just provides a valid IBUS signal... it doesn't enumate the GM5 or anything else, yet the radio works.
If I disconnect the IBUS, the radio says DISABLED.

As the car's still running, and I'm assuming you can unlock it via the keyfob, then the GM5 is at least MOSTLY working... and I'd go back to BMW and ask them to check if the IBUS is dead in your car.
And get them to do it for free if they've charged you £138 for diagnostics that didn't actually do any diagnostics, the cheeky fecks.
 
Hi SK 93 - thanks again for your valuable input, I shall go take it up with the service manager tomorrow. After reading your response I searched for info regarding faulting the K Bus - found this http://www.bmwgm5.com/K-Bus_Troubleshooting.htm. Seems the wires from each module are connected in a star formation and linked on a shorting strip behind the glove box. Removal of each wire should result in the faulty wire (and therefore module being identified). This being the case I don't understand why BMW could not prove the K bus within an hour of diagnostics!

Can I ask you a question - if all of the wires were disconnected from the shorting strip - what would you expect the diagnostic computer to indicate - presumably the K Bus interface would be up all be it not talking to the individual modules?

Thanks again

Phil
 
Update on progress:

I have found an excellent guide on diagnosing problems with the KBUS. I have stripped the glove box out and stripped out the connector where all of the communication wires terminate from each of the modules on the KBUS. Over the weekend I will remove each wire in turn and try to (I) restore the KBUS communication and (ii) identify the faulty module.

Will update outcome.

Phil.
 
Phil,

where are you based as it might be that the BMW software could connect but someone with it on their laptop can, worth a try.
 
HI Mac - thanks for your suggestion. I have just invested in a diagnostics package from another member, so am having a go with that first.

Cheers

Phil
 
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