OBC pin-out : anyone ?.

[emw525E34]

Where can I find the OBC pin-outs ?. would appreciate a complete description.
Since JonK inspired most of us to do the screen mod, I am investigating on ways to relocate the OBC from its current location. Since it is a bulky beast and a dated screen display, I thought , might as well build a small one with few keys that I need. (keys and display screen would be separate).
Plenty of nice backlit LCD screens available and a few support chips to drive it and interface to the OBC pin-out block.

What do you think ?. I am sure it crossed Jon's mind before :)

[PhilipJCaputo]

I say do it! break the ice, and document it well so we can all follow ;-)

[emw525E34]

I plan to do it only if I can get the pinout of what those pins are. It is too difficult to reverse-engineer by taking an OBC apart and retracing the circuits. There is also an issue with the coding plug which may or may not be needed. I am not sure. I think only 520 and 518 needed the plug while 525 onwards does not need it. Can anyone clarify ?.

[emw525E34]

ANother sneaky/smart way is to build an iinterface circuit towards the OBC wiring harness that will interface to a Palm Pilot/ Treo/ PPC handheld. Then write an app to display and do button activation. This is not a bad option for some. But where can one dock such devices in useful location for viewing and button punching ?.

Kinda nice to be able to log data on fuel consumption, trip meter etc. But then, such info should be used/stored in the car pc.

[Jon K]

ANother sneaky/smart way is to build an iinterface circuit towards the OBC wiring harness that will interface to a Palm Pilot/ Treo/ PPC handheld. Then write an app to display and do button activation. This is not a bad option for some. But where can one dock such devices in useful location for viewing and button punching ?.

Kinda nice to be able to log data on fuel consumption, trip meter etc. But then, such info should be used/stored in the car pc.


emw525E34,

I admire your interest, but really, the mpg, top speed, etc are all calculated mostly in the OBC itself. The OBC just gets certain signals from the ECU. I've had the OBC out when extending the wires. It was about 15 pins... so one would think some sort of serial device. But, it looked extremely proprietary. I don't think BMW would release to you their transmission information. It's not an OBDII device that uses common signal-sends. Good luck though!

[emw525E34]

Thanks for your reply , Jon. I figured it would be propreitary. I actually wanted digital fuel left display (code 7). This gives me accurate percent of fill in gas tank. All other stuff pretty useless, maybe except average mpg after a reset button.

Hm... so extending wires for relocation seems the only way if I needed to "reclaim" the space in the centre dash.

PS: I fitted a E46 4 spoke leather wheel to my E34 touring. I did reuse my old airbag and it works real well. Had some trouble with the slip-ring. Reused existing one. Works well and nice feel!. Enjoying it!.

[Jon K]

Thanks for your reply , Jon. I figured it would be propreitary. I actually wanted digital fuel left display (code 7). This gives me accurate percent of fill in gas tank. All other stuff pretty useless, maybe except average mpg after a reset button.

Hm... so extending wires for relocation seems the only way if I needed to "reclaim" the space in the centre dash.

PS: I fitted a E46 4 spoke leather wheel to my E34 touring. I did reuse my old airbag and it works real well. Had some trouble with the slip-ring. Reused existing one. Works well and nice feel!. Enjoying it!.

Picture of how you manages to preserve old slip ring? THanks

[emw525E34]

Dang!. I did not take that pic. My cam ran out of batteries!. I but I describe it:

SlipRing in my E34 had 3 torx size 10 screws holding them to the wheel. The E46 wheel "spline cone" is a little bigger but there are not support alumium around it to drill into. It does have a notch below which I am not sure for what. But does does not get in the way. Initially. I spend an hour fabricating an ABD plastic ring around the spline-cone in the hope of attaching it so I can drill 3 holes for the screws from the slip ring. Did that when when I testfit the wheel, I found that the edges of the plastic slipring were nearer to the cone. Huh ?. E46 splineCone was a little fatter. So I filed off the edges of the plastic mount holes of the slipring harness so the 3 tabs actual held on the cone. Since the inner ring just rotates and outer plastic ring stays put. Thats no issue. As long as the ring is aligned flat, I guess its OK.

Once the wheel mounted, I think (can't see at this stage as its covered) the slipring stays almost flat and inner ring rotates ok. The wiring plug that protrudes into the wheel holds it in place. It appears to work so far. I may need to check and lubricate this periodically.

Hope it helps.

[Robin-535im]

I know the DME pinout is there, and probably the OBC too.

[emw525E34]

Robin,

I don't have access to Bentleys. Could you take a pic and post pls ?. Would appreciate that info.

[Robin-535im]

I would but I don't have easy access to the technology required (digicam or scanner). Perhaps someone else could post it?

[Jon K]

I would but I don't have easy access to the technology required (digicam or scanner). Perhaps someone else could post it?

We need to find someone with a print shop and have the bentley put in PDF format.... *evil grin*

[Javier]

Javier