Originally Posted by jmai86

Bumping this up for a question:
What circuit board is that in the OP's photos? I think I have the same issue but I can't figure out what switch OP is talking about...

Originally Posted by Candace White Thunder

So I bought this 2002 Mini. It didn’t run when I purchased it. Only code is P0705. Was anyone having starting issues with this code? Power to injectors is working, negative pulse not working, also no spark. I’m trying to rule out everything before buying a new computer. Thanks

Originally Posted by numbersix

Boring Prologue:
My wife's 2003 R50 had been running in EP mode for several weeks after being told that she needed a new tranny by BMW... and finally one day decided it no longer wanted to start altogether. I'm in Phoenix and the car had broken down outside of her work in 110 degree heat so I did what I could in the parking lot to get it running, battery voltage was good, sprayed fuel from the rail when depressing the valve, didn't seem to have spark... Towed it home with my truck when it looked hopeless without proper tools (5 miles, I know you're not supposed to tow the CVT on four wheels). Starting issue stayed a mystery for a few days while I waited for an OBD cable to be delivered. I suspected the immobilizer and when the cable arrived, I was right, resynced the key and it started again, but the EP mode remained... Read the codes and they were P0705 PRNDL Input, P1611 Serial Communication to Transmission Failure, P0500 Vehicle Speed Sensor.

Admonition about using google to solve all your problems:
Based on information from google and this forum went down several blind alleys, most information points to the sensors in the following diagram:

Seems logical based on the issues I was having, but actually neither of these turned out to be the problem, and you can deduce this without every turning a wrench. If your car starts, and only starts in Park and Neutral then the safety switch #4 is not the issue, it has nothing to do whatsoever with the shifting process and is an accident of someone's misunderstanding and google's ability to broadcast information that you get that answer at all, it is only a four position switch, ignore it (or at least drain your tranny before removing it because it will happen with or without your consent, ask me how I know). The other sensor in the diagram, Part #1, measures speed at the differential, when disconnected, the speedometer didn't work, so that wasn't it either. So the issue can only be so many things, the ECU seemed fine and it controls the tranny through the GIU, it was getting data back, at least enough to tell it that it was broken...

Tore apart the center console, unplugged everything, (lighter, leds, mirror switches, the actual switch to gear input) and running this way no difference to the car, so as it was too hot to work outside anyway I was looking for wiring diagrams and found the motherload free factory documents for my car.

http://www.bmw-planet.com/2011/11/05...cal-documents/

While looking at the wiring documentation for the CVT, you see something strange you can't really guess looking at a bunch of plastic "Modules" especially if you don't think about the car working on a bus system. There is one communication line (Green + Yellow) used throughout the tranny communication circuit and one ground so since the switch made no difference in any of this, it was (probably) bound to be one of those that was the issue. Pulled the switch of the shifter and found what is inevitable (in between three cup holders that aren't waterproof) in the Mini, a switch corroded by spilled drinks.
Cleaned off the switch and sanded some of the blistered soldermask and found a single burned off trace:

This was on the Red wire on the harness for the switch, which was the Green + Yellow line in the GIU/ECU harness. It was burned off up to the via, so I just jumpered it with a small piece of 30 AWG kynar wire like this:

and, long story made a bit less long, this fixed all of the above codes, switch was able to communicate, no more break in the serial communication to the transmission, no more plausibility issues with the speed sensor. As far as I can see there is only one part regarded by the car as PRNDL input. it is the switch on the side of the selector lever.

I thought about just replacing the whole switch because the fix seemed a little kludgey but after trying to buy the switch and being told that I need to buy the shifter assembly for $500 I don't think I will. Price for the repair went from $6500 to $500 to $0.01 and I'm really alright with that. I'm only posting this so that other people don't waste time like I did.

Originally Posted by gresh

Folks,
I purchased a 2006 R52 that has CVT transmission problems. The trans is in good shape. I have pulled the pan and very little metal in there. The trans will not shift out of low. I have put it in learn mode and cleared the adaptations. I did the low gear learning, but every time I try to do the high gear learning (road), it will not kick into high to get me to 55 mph. I put my OBD reader on it, and I get a P1611 error. I saw this thread on it, so decided to pull the circuit board and have a look. The photos of the extraction and findings are attached. The bottom line, there definitely is some arching that happened with the board because of something leaking down into it, but I dont have the same problem as the others. Mine looks like it might have shorted one of the transistors on the board. I have ordered a replacement shifter, which has the board on it. Thats cheaper than trying to buy the part from Mini ($40 v.s. $788). I will keep you posted on how it goes. I think that to start out, I will remove the board from the new shifter and put it on the one thats already in the car.

Didnt have to remove this. Since I didnt know where the board was located, I did.

The board is the black piece with the white sticker in the middle of the picture.

You can see that something wasted. That big round spot is where the board was arching and heating up.