Hey everyone. 

I’ve got a Non-S 2012 Mini Cooper (R56 LCI, 1.6 NA, Aisin 6-speed automatic / Steptronic) and I’ve been chasing a really weird transmission/shifter issue the last few days. I wanted to write the full story and then ask a couple of specific questions at the end.

I’ll attach a photo in the comments of the 8-pin connector I unplugged under the shifter.

The symptoms (at the beginning)

* Car normally drives fine in D and DS.
* Then suddenly one day, while driving in D, the cluster started rapidly flicking between D and DS on its own, multiple times per second:
   * The car *felt* like it was in DS (higher revs, sportier behavior etc...),
   * The display was flashing back and forth: D → DS → D → DS…
* I was not touching the shifter.
* Shifting P–R–N–D worked, but DS wouldn’t always engage or disengage properly.
* If I shut the car off and restarted. Since I've restarted the car I've put the transmission through P, R, N and D. No problem whatsoever. However I was physically able to put the shiter to DS but it was stuck on D. DS was completely out of the picture.
* Few hours later I've restarted the car and was able to use it perfectly. No issue in between changing D-DS etc... However in 2 days the problem would come back.

So basically:  
Random, self-triggered D/DS switching, especially while driving.

First mechanic visit – “shifter handle is coming loose”

I took it to a local auto-electric / transmission guy.

* He connected a scanner, said something along the lines of:
   * “The shifter handle / mechanism is loose and needs repair, it’s not a gearbox failure.”
   * Quoted me roughly 150-160 USD
* I left the car there. When I came back:
   * The car was up on the lift,
   * Exhaust was removed from the rear section,
   * He had partially disassembled underbody stuff to access the transmission side.
* Inside the car, the shifter assembly had been removed and reinstalled – he said he rebuilt/adjusted the shifter linkage/handle.

He charged the 150-160 USD as agreed. After getting the car back:

* I drove about 30–35 (and then 150 km so a total of 180 km-ish):
   * D and DS worked fine,
   * No random switching,
   * I even did some WOT pulls in DS uphill and on flat road – no issues.
* I thought, *“OK, seems fixed.”*

Then a day or two later, problem returns

* The exact same symptom came back: While in D, it started flipping between D and DS by itself.

So at this point:

* Mechanic’s “shifter repair” clearly didn’t permanently fix the underlying issue.
* I started reading online about Steptronic D/DS issues and found threads about error code SW 523A (Steptronic switch) and people talking about the shifter illumination / steptronic board under the gear lever causing trouble.

My own test – unplugging the 8-pin connector under the shifter

I decided to experiment a bit (carefully).

Under the shifter, on the driver’s side, there’s a multi-pin connector (8 wires) going into the gear lever / shift indicator module (the plastic piece with the PRND letters that lights up at night).

What I did:

1. Exposed the shifter area.
2. Found the 8-pin connector going to the shifter’s internal PCB / illumination / steptronic module.
3. Unplugged that 8-pin connector entirely.
4. Started the car and drove it for roughly 2-3 km's.

Result:

* The PRND/DS illumination on the shifter is now completely dead (no light around the letters).
* BUT:
   * D works normally.
   * DS works normally – I can pull the shifter to the left into DS and the car goes into sport/DS mode as it should.
   * Manual +/- works normally – I can tap up/down and it shifts as expected.
   * The cluster also correctly shows D, S/M, etc.
   * No random D↔DS switching anymore.
   * However I'm compelled to state this - I've only tested the car roughly 2-3 km's after I removed the connector.

So with that connector unplugged:

* The car drives perfectly,
* The only “loss” so far is: no backlight / illumination on the shifter gate.

My questions to the community

1. Is it safe to drive like this with that 8-pin connector unplugged?
   * Shifting, D, DS, manual +/– all work fine.
   * No warning lights,
   * Only the shifter illumination is gone.
   * Can I run the car like this long-term without hurting anything?
2. Does this behavior make sense to you?
   * That the internal shifter PCB / illumination module could be shorting/feeding bad DS signal and that removing its connector stops the false D↔DS toggling but still allows normal operation via the main range switch?
3. What’s the *proper* fix here?
   * Replace the entire shifter assembly?
   * Replace just the connector/harness (“Automatic shift indicator connector and wire”)?
   * Open the shifter, inspect the small PCB for cracked solder joints/oxidation and repair it?
4. Could that previous “repair” (removing the exhaust, messing with the shifter, etc.) have made this worse?
   * The mechanic said “shifter handle is coming loose” and charged me to “fix” it,
   * But since the issue came back and I can make it disappear (still, not sure it's disappeared completely. Need to test it more) by unplugging this connector, it looks more like an electrical/PCB issue than mechanical.
5. If anyone has wiring diagrams / pinout for this shifter connector on an R56 with Aisin 6AT, I’d love to know exactly:
   * Which pins are illumination only,
   * Which (if any) are DS/steptronic signal lines,
   * And whether unplugging it leaves the TCU simply ignoring that redundant path and relying on the main switch.

Thanks a lot in advance – I love this car and want to fix it the ***right*** **way**, but also don’t want to throw money blindly at the transmission.

2012 R56 Mini Cooper (Non-S) (Auto shifter - Aisin 6AT) randomly switching between D and DS – mechanic “fixed” shifter, problem came back – now unplugged this 8-pin connector and it’s gone. Is this safe?