SMG Resistor Mod for E60 530i

[boostinben]

Hey everyone,
This may be a bit of a longshot but recently on a drive through sanfrancisco i experienced the classic going into gear failure from a stop in traffic with my 2004 SMG 530i I beleive this to be related to the SMG pump temp sensor going into a failsafe mode due to exesssive temp reading. I say that because the car seemed to be fine after being given a little bit of time to cool down and also when i got through the city and further up the highway it was fine as well.

After the episode (where i nearly got stuck on the golden gate bridge) i jacked the car up and changed both the hydraulic fluid in the pump & the transmission fluid as well as swapped out the salmon relay under the hood that controls the SMG . I have not had an oppertunity to test it in traffic since but intend to try put it in a stop and go traffic situation today if possible (its damn hot here today)

I do however want to persue the "SMG Resistor Mod" for some added protection if the temp of the unit is in fact the issue i am facing.

I did a lot of reading on the topic, most all referenced and DIY articles I have found are related to the e46 M3 crowd performing the "mod" where a resistor is run between the temp sensor on the smg pump and the ECU to trick the computer into thinking the SMG pump was at a lower temp thanit actually is.

e46 SMG cars have an updated Pump / resivour setup that is accessed from under the hood, where as my older 530i has the SMG pump / res directly mounted on the side of the transmission.

All of the articles seem to identify a white wire that needs to be spliced for the resistor, I was not able to locate this wire in the fuse box under the hood, so I then looked directly at the SMG pump and the temp sensor (I beleive) and found that it has 3 wires red/white, brown and purple.

First of all, can anyone tell me if they have or know of anyone who has performed this mod on the older SMG pump?
Also, can someone confirm if this is actually the temp sensor I am looking at and if they know which of the wires i would need to splice in the 3k ohm resistor?
Picture below for reference to the sensor under my car:



Any help would be appreciated! I am hoping that i can go down this path before i look at more costly / complicated areas like replaceing detent springs or even the entire pump.

[Synisalo]

Well, I cant say if that's the Temp sensor or not, but when you see three wires like that, it generally indicates a TTL circuit. The brown wire is the ground. The red one is a 5v power feed, and the purple is the signal return from the sensor. I had a similar sensor issue with a E36. *IF* that's the sensor you need, you'd cut the red wire from the sensor, and install your resistor between the red and purple wires. this will fool the computer into thinking its getting a normal signal from the sensor. Although, from this picture, that looks pretty simple to just replace. If its ok, and your temps are really that high, fooling the computer may be a good short term fix, but there'd be some issue with heat that needs tending to before you toast something really expensive.

Good luck!