Hey everyone,

just wanted to know if anyone has heard of this.

I was driving my wife's Mini (2010 R56 S) to my mechanic for a couple of faults that kept popping up and I couldn't narrow down the issue. On the way there, transmission goes into limp mode. Ended up getting it towed the rest of the way to the shop. The mechanic quickly diagnosed the initial issues I was bringing it in for and cleared the codes. Runs super smooth now, but trans fault is still there with P0720, P0715, and P0712 codes.

Mechanic starts to dive deeper and identifies that the speed sensor is shot. He also found that transmission fluid has wicked its way through the harness all the way to the TCM which might have fried the TCM. He has bowed out with messing with the wiring harness especially since the fluid made its way to the body harness itself. Sp, the car is now done and the wife is looking at a 2022 F56 S so Ill get it from the shop and start stealing parts for my other 2010.

However, as anyone seen this with Minis? I know some VWs have had issues with some oil sensors doing this, but I hadn't heard about it on Minis.

 

Apparently the internal transmission harness connector or the fluid temperature sensor seal fails, allowing pressurized fluid to crawl inside the copper wiring all the way to the Transmission Control Module (TCM).

 

Yeah, just shocked it made it through two wiring harnesses without any issues til it nuked the TCM.

 

Yes I have heard of this, but Maybe is right. Wire is copper, a wick is made of cotton (absorbs moisture). Try to soak up a spill on your counter with a piece of copper.

A few years ago, a lady from church brought me her Kia, after taking it to the dealer for a recall.. She came home with a $4000 estimate to replace the engine wiring harness because the harness had "wicked" up oil and dumped it into the PMC connector. I'm still not sure how the copper wire wicked up oil against the force of gravity since the PCM sits about 18" above the oil pressure sensor. The dealer didn't even try to clean up the connector. They just sent her on her way.

Turns out, the oil pressure sensor had failed and high pressure oil was forced into the electrical connector wire and, in turn, make it all the way to the PCM. We changed out the faulty sensor, and cleaned up the PCM connectors male/female connections. She's been running fine for the last 4 years.

 

Nice to know. My biggest worry is whether it made it inside the TCM and fried it. I got the car home Sunday, and when I was getting it off the trailer, the transmission errors went away and no more limp mode. Im going to take that as a good sign the TCM is fine. The output speed sensor tested open at the mechanics though so it should have thrown it into limp mode instantly. Im guessing either the fault with the sensor is intermittent or the fluid receded enough to not cross contaminate the pins during my quick move of the car.

Ill end up cleaning the wires and connectors as best I can and swap in new sensors when I get time to drop the valve body this summer. Luckily, I have a parts Mini parked right next to it to steal anything I need.