The SME module, or System Management Unit, in a BMW is a battery management system (BMS) that controls the high-voltage battery. It monitors the battery’s charging process and health.
If the SME module is faulty, the dealership wants you to replace a new one which takes a long time and is expensive.
There are 3 BMW SME solutions so far!
1. Before resetting, make a backup with “Online ISTA”. Then reset and restore. (By pass ‘tester way’)!
2. If you don’t have an “original SME” then you need an “AOS” tester. Ista online…
3. Manually erase 4 bytes of “crash” data from the “eeprom”. Special note! This doesn’t work every time. It’s located in different places every time!
If the car is 2022 and below, it is “offline”, otherwise all “battery series” are read online.
Here we will show how to repair BMW SME module using CG100X programmer.
This is the SME (System Management Unit) High-Voltage battery cell module.
Remove and disassemble the SME module.
Remove the 4 screws on the top to open shell.
Disassemble the control interface.
Remove these screws.
Lift the cover.
If the vehicle collides, these two blown fuses will short-circuit.
So we MUST replace these two blown fuses before repairing the SME module !!!
This is the BMS module we need to repair.
Disassemble the SME module.
The CPU (Infineon TC275) chip controls the battery data.
We will read and write this module with CG100X.
Run CG100X software, go to BCM function.
Select BMW- SME- I3/I4/IX3-TC175 (read/write).
CG100X will show you the wiring diagram.
Zoom in the diagram and connect module with CG100X via pro v2 adapter.
Then read the Dflash data and save.
Send your data to CG engineer or 3rd party resource to modify data.
Then select the modified data and write back to the module.
Wait until the writing chip is completed.
Then reinstall SME module and install to vehicle.
You will also need to program SME module with ISTA in order to work properly.
Xhorse Multi Prog will also repair BMW SME HV battery cell module in this way. Here is the BMW SME pinout to multiprog.
http://blog.obdii365.com/2025/01/21/repair-bmw-sme-battery-module-with-cg100x/
