Hi guys,
I'm working on our 2008 X3 and I recently got the 3 lights (4x4, brake, abs). I lifted it up on the rack and just as I expected, the internal gear for the servomotor was worn smooth.
I've since replaced the gear and now when I start the car, it goes straight into 4x4 rather than 2wd.
Upon plugging into the ISTA-D, I'm able to read out the amperage and degree position of the servo motor and can watch the degrees and amps sweep when I start the car.
When I go into "vehicle management" > "service functions" > "Powertrain" > "Transmission control unit VTG" > "Repair" > "ABL Transfer box" repair" and select any of the options to reset the transfer case adaptation, it will read the calibration resistor as "Code G", then attempts to calibrate the servomotor. I hear it move back and forth in the case, but it last about 4 seconds and then results in "The function could not be performed fault-free" "Try again 1 Yes/ 2 No".
Doesn't matter what I do, it always results in this error.
The car was operating perfectly before the gear died, and now I can't get it to adapt again.
Any pointers?
Thanks
I used the NT520 to reset mine but i think you go into Oil Change instead of Repair for the adaptation reset.
What do you mean by it goes into 4x4 instead of 2wd?
You should not have to reset the adaptation because of this failure!
If re-assembly of replaced gear, servo-motor to the transfer case and both cables/connectors are attached correctly to the servo-motor then (4x4, brake, abs) should disappear immediately after the car is driven a few yards away.
Did you ever figure out how to solve the ISTA/D "The function could not be performed fault-free" problem? I am experiencing the exactly same problem and am stuck with BMW triad of lights at the moment and "VTG: Faulty calibration" code.
A little bit of history about my car:
I had triad of lights so I replaced gear on my X3 and did not reset anything with ISTA/D. Triad of lights went out on their own.
However, my car was juddering big time on sharp, slow turns. So I also replaced TC fluid and successfully reset adaptations through ISTA/D (TC oil change wizard. Not the one you picked up). This helped a lot with juddering.
However, there was still a little juddering when car engine heated. So I took servo motor out again. Greased it liberally, put back and this time picked the "vehicle management" > "service functions" > "Powertrain" > "Transmission control unit VTG" > "Repair" > "Exchange transfer case servo motor". And that's when I ended up in the same situation as you.
I think this either means:
1. we both picked the wrong ISTA/D "service function" that triggered this issue. I.e. a software glitch.
2. when I took servo motor out second time I may have not put something correctly back in.
Although my transfer case motor tested fine when it wasn't bolted to the car, replacing it completely was the only way I was able to get ISTA to calibrate properly. I bought an OEM motor, but it's likely that an aftermarket motor would have fixed the problem as well.
Cheers
Thanks a lot! This gives me a hope that my problem hopefully is also in servo motor.
Few followup questions:
1. What do you mean with "my transfer case motor tested fine when it wasn't bolted to the car"? Was the test just to observe that the servomotor gear spins under no load?
2. Did you also try to isolate issue to the transfer case servo resistor by replacing it during your troubleshooting?
3. Do you recall if you by accident somewhat pulled out worm axle from servo when replacing the gear? The second time I opened up the servo I was not careful enough and pulled out the axle a little bit out. The first time I was super careful and it did work fine.
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