OK I know this is an old thread, but please don't yell at me. I have a problem and I need an answer by tomorrow morning, so please allow me to ask.

I have discovered a faulty connector to the resistor on my transfer case actuator motor. The connector is broken and the wires some times make contact but some times they do not. So I get an error in my error memory.

A local BMW shop has a new resistor and they are going to replace it for me, but I've read somewhere, that the resistor has to be programmed in the car, using DIS/GT1. Unfortunately, the electrician of that shop is on vacation and the owner told me that programming the resistor is NOT necessary.

For those of you who have changed your resistor or your actuator motor, how important is the programming of the resistor in the car? In other words, what will happen if the resistor is not programmed?

Many thanks for your attention and sorry for reviving an old thread.

Yes, you have to reprogram the transfer Case using the Service mode under DIS/GT1 so that the clutches and motor recalibrate correctly.

If you don't, and the new resistor is very different value from the previous, overtime, you will possibly do damage to the clutch pack.

When the "shop" changed my actuator (inc resistor), they said they had "programmed" it which after driving for several miles, found even though it is a new resistor/actuator, I was still in two wheel drive as the clutches weren't engaging correctly. I also got Resistor Calibration Error codes. I ran the routine under DIS and it recalibrated correctly.

I know people on this forum say you don't need to (and you definitely don't if you use the same actuator motor and resistor), but if the BMW TIS Manual states it does, and from my experience, I definitely suggest you get it done.

:iagree:

I would say it is important to calibrate it. If the calibration is incorrect, too much actuation would stress and or break the actuator gear, and too little would cause excessive slip in the clutch pack. Both are avoidable by doing the repair properly.

OK guys thanks. I'll try to have the existing connection repaired until the electrician is back, and then I'll changed the resistor and have him program it.

Thanks again!!

OK guys, I temporarily fixed my resistor connector and the car is running fine (no error codes shown by INPA/Ediabas in the transfer case.

I also bought a new resistor, but I'll wait until the electrician returns from his vacation, to have it installed.

For those of you who have done it, and just in case the electrician doesn't know how to do it, could you please describe the steps necessary to do the calibration with the new resistor for me? I would appreciate that very much.

Thanks again for your input.

If your service guy doesn't know how to do it, he shouldn't be messing with it.


I don't have the manual, but see this thread for some more info. ECS was selling the fluid, and several of us felt that there really should be a reminder to people to do it properly, and not ignore the reset procedure:

http://www.xoutpost.com/bmw-sav-foru...available.html

See this thread, starting at post #14, and the attachments in post #20:

http://www.xoutpost.com/bmw-sav-foru...sfer-case.html

Note that resetting the adaptations is the procedure to be done after changing the fluid. That is a separate and distinct procedure from the programming involving a new classification resistor.

Edit: In the parts catalog, the resistor is sold as a set. That implies that it may come with a number of resistors of different values. The BMW service procedure describes putting the actuator on a bench test when it is made, and matching the resistor to the actuator. So, it will be interesting if there are multiple resistors and it becomes necessary to determine which one to use (they compensate for different amounts of play in the actuator and clutch pack). Or, there may be one resistor, but that begs the question of why it would need to be a separate part and not part of the actuator then. Let us know what you find out.

Interesting. And you are obviously right, since the realoem.com site indicates for the resistor, that they are a set!!

Am I correct in assuming that I should buy a set and use the one whose resistance value is closer to the one currently in my car?

OK, this is becoming more and more strange. According to the local shop here, the actuator motor is sold with a resistor on it, as a package. Now during assembly of the car, the resistor is selected based on the tolerances etc of the transfer case clutch package, how on earth do they select which resistor to use, on the spare parts actuator motor??

The value of the resistor that came with the actuator motor, has to be encoded back after deleting the old value using GT1, for instance it may show up in GT1 as class B and the old one was class C, it is important to the life of your tranfere case, you should change the oil also at the same time, and do new adaptation so everything works great, I did mine a couple years ago and had no problem up to the sale of my car.


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That is exactly what I would do myself, assuming that you get a selection of various resistance values when you order the part.