SOLVED-Steering wheel controls and cd clock intermittent

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burtoboots

Member
Hi, first post from me having just bought a 2006 E85. Looks like a great forum.

I'm finding the steering wheel controls (vol, track skip) are intermittent. But doesn't seem related to steering wheel movement. Instead they either work fine for half a journey, or not.

I have also noticed that at same time steering wheel controls are inop, the clock display on the business cd switches to --:-- instead of showing the correct time from OBC.

There's a OEM BMW iPod cable fitted. When you work thru the audio sources on the head unit you sometimes get magazine empty (iPod connection I guess) and sometimes that's not an option.

Makes me think of there a bus issue?

The car has been very little used for three years before I got it, so battery may be weak.

My plan of attack is to remove the OEM iPod interface just in case this is the culprit. I'm not going to use it anyhow and can work backwards from the fitting TIS I have found.

But wondered if there's any other suggestions? Would a weak battery cause this even when engine starts and runs fine?

Thanks for reading to this point!
 
I was first thinking kbus issue at first (used for the time to sync from the dash cluster, and for the steering wheel controls), and then saw your iPod thing, and that re-enforced my thoughts

I think you're on the right lines for now

You should be able to remove the iPod integration by just removing the radio from the dash, and then removing the two smaller connectors from the large radio plug (should be obvious once you're looking at it). That might be easier than chasing down the control units etc in the short term.
 
I have removed the iPod integration from the car and re-populated the radio connector to put it back to factory.

All was good for 20 seconds or so, steering wheel controls working, big smile on my face, ... and then it reverted back to not working.

One thing I did notice on the radio connector is that the white cable looks to have been broken and repaired with some nasty inline terminals. But I don't think this is the kbus connection

My diagnostic cable arrives shortly so once it's here first step I'll try is to see which ecu doesn't want to talk to me.

Anything else recommended in the meantime?
 
Kbus is white, with red and orange dashes, I think.

It could of course be that radio itself is faulty, but hopefully the code scanner will provide some insight
 
Update now I have all the tools to look at this properly

Radio now showing --disabled-- permanently.

Ista cannot communicate with the radio, but can communicate with the other modules on that kbus leg of the ista ECU diagram

Removed radio and measured voltage at the radio connector with respect to battery negative.

Battery only (no engine running)
Pin 9 kbus 11.6v - with occasional drops. Can trigger drops by putting hazards on etc
Pin 15 power 12.0v

Engine running
Pin 9 kbus 13.6v - with occasional drops as above.
Pin 15 power 14.0v

I think this tells me kbus is good?

So suggests that the radio should be replaced. Before I jump to that and get one bought, any other suggestions from the forum?
 
I have had the same problem you describe, and more. I battled the Kbus for a year.

At the end of the day mine was down to two main issues. The module on the floor between the two seats was damp and I had to remove the module, dry it and resolder a load of dry joints, that brought most of the electrical issues I had with the car back to life but left the steering wheel controls intermittent and the Radio disabled, no clock etc.

That was remedied by accessing the large connector behind the passenger seat and behind the "vent" in the plastic trim that has the roof control module behind it and cleaning and reseating each metal pin inside the connector as it had a short to ground somehow. After doing that the radio and clock sprang into life again.

In short, my issues were dry joints and a short to ground on the K-Bus. Your issue may be in the wiring somewhere else but I would wager the issue will be similar.
 
Thanks for the information @SimonAW. I recall INPA/ISTA unable to get a response from satellite airbag modules - this could point toward the airbag module that sits between the seats as a common cause although the airbag module itself did respond to INPA/ISTA.

@SimonAW I'm guessing that "module on the floor between the two seats was damp" is the central airbag module?

I have a radio arriving shortly - I'll swap that in as its easy to do - if that doesnt fix it then looks like airbag module and its harness connector is next up to look at - then after that the other module behind the passenger seat.
 
I think from reading something @enuff_zed wrote before that if you can access the airbag module plug by removing the coin holder behind the handbrake then you can unplug that and if it is the problem then everything else should start working again.
 
Fitting a replacement business cd radio has solved this. I bought the most recent one I could find on eBay (date code on the label)

Original 6976888 date 11/05
Replacement 9173686 date 12/07

ill summarise for those who come across this in the future:

Only kbus type issue I had was intermittently steering wheel switches not working and at same time radio clock was --:--

Once steering wheel switches returned to life, clock on radio would then display correctly.

Removed BMW I pod interface. No change

Tried disconnecting battery negative overnight to fix this intermittent issue and then radio permanently "disabled"

ISTA could not connect to radio.

Checked kbus wire at radio multiplug pin 9 voltage with respect to battery negative. Showed 12v with occasional drops - looked like kbus ok at radio.

Pray to the gods of ISTA and INPA and hope I'm not going to be working thru every kbus module....

Switched radio for replacement, all good

Oh, and don't forget to eject your favourite cd from the radio before you disconnect it to switch for the replacement unit 😕
 
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