[ogmilokush]

Was told to update my transfer box via "Full Stock Flash". Completed successfully then tried to flash the RWD. Mid flash it gives me an error and leaves my transfer box in boot mode.

After various methods of rebooting and power cycling the car. My car is still showing a Christmas tree on the dash board. App says I am in "boot mode"' and need to do the "Full Stock Flash". Of course now I get the error every time trying that.

Connected to ISTA+ and the car is showing the following codes:
S 0270 No communication possible with: Transfer box control unit
S 0557 Programming abort: Transfer box control unit

Also these 3 codes which I assume are associated with having no transfer box communication:
CDA426
D016E4
D356E4

Any idea how to start fixing this? I am very frustrated having paid $160 to ruin my perfectly functioning 335. Worst case scenario I will have to replace the unit, and with my car being a rebuild title with external mods no way BMW will do it. With this winter season I need my XDrive system functional to get to work.

[Boostedphil698]

Originally Posted by ogmilokush

Was told to update my transfer box via "Full Stock Flash". Completed successfully then tried to flash the RWD. Mid flash it gives me an error and leaves my transfer box in boot mode.

After various methods of rebooting and power cycling the car. My car is still showing a Christmas tree on the dash board. App says I am in "boot mode"' and need to do the "Full Stock Flash". Of course now I get the error every time trying that.

Connected to ISTA+ and the car is showing the following codes:
S 0270 No communication possible with: Transfer box control unit
S 0557 Programming abort: Transfer box control unit

Also these 3 codes which I assume are associated with having no transfer box communication:
CDA426
D016E4
D356E4

Any idea how to start fixing this? I am very frustrated having paid $160 to ruin my perfectly functioning 335. Worst case scenario I will have to replace the unit, and with my car being a rebuild title with external mods no way BMW will do it. With this winter season I need my XDrive system functional to get to work.

Sounds like the transfer case control module died. You can try disconnecting and reconnecting it but it may need to be replaced. To be honest, flashing the car back and forth to go from RWD and Xdrive will brick the control unit at some point if you flash it too much. Best to leave it as AWD all the time.

[happyhippo]

Originally Posted by Boostedphil698

Sounds like the transfer case control module died. You can try disconnecting and reconnecting it but it may need to be replaced. To be honest, flashing the car back and forth to go from RWD and Xdrive will brick the control unit at some point if you flash it too much. Best to leave it as AWD all the time.

Why would flashing it often may brick control unit ? Sounds a bit like software problem with xDelete.

[Boostedphil698]

Originally Posted by happyhippo

Why would flashing it often may brick control unit ? Sounds a bit like software problem with xDelete.

It's like the DME, if you flash it so many times, it'll brick.

[oem.plus_440gc]

Just listened to a podcast that discussed tuning, and most ECUs (DME/TCU/etc) have a flash counter built in and are programmed to automatically brick itself if it is flashed too many times (I think it's a safety feature to stop theft or hacking). Hence why most (likely all) tuning platforms reset that flash counter each time you flash the car in order to avoid a potential accidentally bricked ECU. Hopefully that's not what happened with XDelete.

You mention it being a rebuilt title car. If a previous owner had done reprogramming of the trans prior to you getting it and without the flash counter being reset, it could have bricked itself in theory.