Trans wiring harness issues. 4x4, trans malfunction, DBC, DSC, AWD, brake light on

[Toothbrush]

I have no idea how hard it would be to replace that harness, but curious if doing that is something you're considering. Seems like there's an issue that's directly related to the connection between the harness and transmission electronics, so it would make sense to correct that issue before trying to track down others that may or may not exist.

[brokenbim]

Ok. The last time i drove is when I got all the codes and lights from my last post. Today it started up again with no code lights on the dash or idrive. I got it on ramps and checked the ohms to ALL the transmission wires going into the plug with the multimeter again. I stuck one prong into the plug, the second prong I picked into the wire, more than a foot and half up from the plug. I had a 0.0 ohm reading with all the wires. (I also made sure the plug terminals are pushed out like they should be.) I then put dielectric grease on the plug end and plugged back into the mechatronic unit. Now immediately after starting the car, I have all the code lights back on, and now no light on the shifter knob. (It did start though)

So I almost sure if the problem is in this location, its in the mechatronic unit, not in the cable or plug leading to it. I just bought this car a year ago and this plug was messed with, so I presume they knew something that I dont... yet.

So my questions are: will I be able to check the mechatronic unit's internal plug somehow for continuity if I drop the valve body again? I know the unit is sealed. And yes, my biggest concern is unnecessarily tearing into a very expensive transmission, and not being the issue. Thats why I was hoping someone here might be able to help at least narrow it down using their experience, or by the code combination . It does have a new battery.

Let me also add again that the last few short drives were fine until about 50mph, going into 4th or 5th gear, pauses and then kicks itself down abruptly to a lower gear with "gear shifter malfunction". Thats gotta mean something or maybe coincidence? Idk...

[ard]

I’m not complaining about the resurrection- good idea, it’s the same issue.


I’m commiserating that you’ve been hassling with this for almost 3 months…..

[brokenbim]

Im sorry guys. I thought i responded. It did turn out to be the stupid mechatronic unit sleeve. I'm having trouble remembering but i think I bought a cheap chinese one from amazon or ebay that didnt work.

So then I bought another one somewhere that cost twice as much thinking I had a quality one; still no work.

So then I finally smartened up and got one from FCP euro and finally had success. I now have four of them...

I also ended up sticking sewing needles through the harness to help with any bad connections. Not sure if it did anything or not.

Biggest takeaway, get your parts from a reputable company. There are only a few to choose from.

[ard]

Originally Posted by brokenbim

I
I also ended up sticking sewing needles through the harness to help with any bad connections.

Huh?!?!?!?

[brokenbim]

He guys. Unfortunately I'm back again in this terrible thread. A few weeks ago the vehicle started showing a "shift lever malfunction" warning, which was the first time this light ever came on. It would come on for a few seconds, and then go off. still drivable with no issues. (Maybe kicks the trans a little when it comes on during acceleration.) Continued to come on more frequent with time.

I did buy and install a quality mechatronic sleeve from fcp euro the last time. But when i inspected plug connection today, trans fluid ran out of the sleeve and down my arm. Guess I now have a return to fcp.

before clear.pdf

after clear.pdf

***Replaced the mechatronic sleeve with new. That stopped the trans fluid from leaking and the shifter light cause was a blown fuse located under passenger floor dash. Will see what else happens...