Unable to calibrate VTG Transfer Case

[jfandl]

Looking for some guidance after some hardware issues.

• Transfer case started having a grinding feeling while accelerating. Two weeks later, the VTG reported it lost communication.
• VTG is dead, holds the magnets in a locked position when the circuit board is attached to the magnet (Yeah, I opened it up)
• It seems the oil in the transfer case evaporated (leaked out ) and damaged the internals.

Replaced the VTG with a used one, wasn't able to calibrate it. Replaced the entire transfer case with another VTG and it still isn't able to calibrate. (Donner transfer case 46K miles - was empty - fresh fill with BMW DTF-1)

When I use ISTA to perform the Transfer box repair, select old unit cannot be read, manually enter the 4 digit MPT code from the transmission. Followed the process to initialize, says it wrote the value to the memory. Run/Stop, then Run/Stop with 10sec pauses per the instructions and then it simple returns to the service menu (I believe it's supposed to provide some feedback if it's working normally).
If you try to calibrate as you should in the next steps, it says "No valid calibration value stored in the VTG control unit" Run the Replace Control unit service function - That's what I just ran.

I have been unable to calibrate the unit - It seems many people had this issue but I struggle to find anyone with a solution. Do I need to drive it a little for the fluid to saturate everything? I only drove it 2 miles so far.

Any ideas?

[jfandl]

I drove it 60 miles and tried to calibrate again but still no luck.

After further testing, If I use ISTA to issues commands to the VTG controller (LMV), I found the following:

Reset
Activate solenoid - when I execute I hear the unit make noise for 1/2 a second then stop, returns incorrect state or something like that.

If I make further attempts to activate the solenoid, all is quiet with the same error. Once I hit reset again, then execute activate solenoid, I hear it again for 1/2 second and then nothing.

It has done this with the original Transfer case and two different VTG's. I must be missing something, right?

[stocktree]

Could it be you have a wiring or control module issue?

[DenBel]

Had same issue on my e70 ended up replacing with new transfer case. the mpt number is on transfer case itself not the transmission. I think your used transfer case is bad…

[jfandl]

Still dealing with the issue I found there was a pregnant capacitor inside the original VTG so I ordered a new cap to replace it. Planning on soldering it in this weekend and give it a go. Will keep your posted.

[tlow98]

Good find. Thanks for keeping this updated. It’ll likely help a bunch of people over time

[jfandl]

Still no resolution. I bought a used VTG AND a new S-Tec SO02547 VTG

When I try to activate the VTG, after coding, it says values were successfully written. Then I try to calibrate it, enter in the 4 digit transfer case code and it says "No valid calibration value stored in the VTG control unit".
First run the Replace Control Unit service Function which is what I've been doing.

It seems the VTG that came with the transfer box, the used one and the new one all exhibit the same behavior so I suspect it's not the VTG.

Power is battery voltage at power and ignition on the wiring harness. 45 ohm both sides of the Flexray

When I clear fault codes and the reset VTG (through ECU function) - I get a Parking brake reduced and Brake error every time. There are NO fault codes stored but the traction control light stays on.

[yupetc]

Originally Posted by jfandl

Still no resolution. I bought a used VTG AND a new S-Tec SO02547 VTG

When I try to activate the VTG, after coding, it says values were successfully written. Then I try to calibrate it, enter in the 4 digit transfer case code and it says "No valid calibration value stored in the VTG control unit".
First run the Replace Control Unit service Function which is what I've been doing.

It seems the VTG that came with the transfer box, the used one and the new one all exhibit the same behavior so I suspect it's not the VTG.

Power is battery voltage at power and ignition on the wiring harness. 45 ohm both sides of the Flexray

When I clear fault codes and the reset VTG (through ECU function) - I get a Parking brake reduced and Brake error every time. There are NO fault codes stored but the traction control light stays on.

I've dealt with this same issue on our previous X5 (it's an E70). I also did replace the entire transfer case, replaced two actuator modules to no avail. The car drove fine and it just shows a traction control error on the dash which is annoying enough. I ended up selling the vehicle to a local dealership because at that time the offering for cars in the States was very preferrable. And I ended up getting the F15 X5 which so far hasn't had any of this issue. Anyway, I also did what you've done, used ISTA to run its MPT number and tried to reset it to work, my error says something about the Flexray communication value fault between the traction control and the VTG module.

I'm subbing this thread for more updates in case I also run into the same issue again.

[jfandl]

SOLVED: I can finally close this out: the problem was the used transfer case I purchased was defective. I received the unit without oil, filled it with fresh oil. Put on about 500 miles on it, decided to check the fluid. I pulled out what looked like melted coffee ice cream. I refilled with fresh fluid again, still no calibration. I worked with Steven over at TCBMWX5 and he felt the clutch pack was stuck or the calibration shaft was worn out. I bought a rebuilt transfer case from him, put it in, calibrated immediately. Problem solved

My advice for other people with transfer case issues: buy a rebuilt one. Too many people on the forums have tried to buy a used one, as I did, but clearly there are issues with these units when they sit around. I hope this helps others avoid all the headaches.

If you try to calibrate the VTG and you hear the click and the motor runs for up to 3 seconds then stops, you most likely have a good VTG and bad transfer case. When the transfer case is working correctly, you should hear about 5 or 6 clicks as it does it's checks.