BMW G21 330e SME2 HVS 01/02 – Battery Module Replaced, READY OK, SOC Missing, Active DTC 21F1C3 – Need Help

Hello everyone,

I'm looking for technical assistance with a 2020 BMW G21 330e (PHEV) equipped with an SME2 HVS 01/02 high-voltage battery management system.

Vehicle history and repair:

Originally, the vehicle had a faulty HV battery module. The vehicle could not charge from the external charger, and the electric drive was not operational.

I replaced the faulty battery module and rearranged some of the battery modules and their CSC monitoring boards.

After the repair and clearing fault codes:

• The vehicle can enter READY mode.
• The electric motor works and the vehicle can drive electrically.
• Charging from the external charger started working again.
• The HV battery has been charged.
• However, the instrument cluster does not display the battery SOC or estimated electric range.
• SME-related fault codes remain active.
• Fault code 21F1C3 returns immediately after clearing.

Software and diagnostic tools available:

• ISTA+
• E-Sys 3.40.1
• E-Sys 24.06.01
• BimmerUtility
• Deep OBD / EDIABAS
• ENET Ethernet interface
• PSdZData

What I have tried:

1. Checked HV battery module voltages and CSC communication.
2. Cleared fault codes using diagnostic software.
3. Attempted SME-related service functions in ISTA+.
4. ISTA requests an EOS test code / validation to complete the relevant procedure.
5. Investigated SME HVS 01/02 cell data restoration and security authorization.
6. Read the SVT Actual using E-Sys. The SVT contains 25 ECUs, including SME2.
7. Checked SecureDiag certificate status for ATM2, DKOMBI4 and HU_MGU. All certificate and binding checks returned OK.
8. Generated a CBBRequest JSON file, but it contains ATM2, HU_MGU and DKOMBI4, not SME2.

Current situation:

The vehicle is operational in READY mode, but the HV battery system does not appear to be fully validated or commissioned following the module replacement.

I would like to determine whether the remaining problem is related to:

• SME2 stored cell/module configuration data.
• CSC module identification or assignment.
• An incomplete HV battery replacement commissioning procedure.
• A missing EOS validation or security authorization.
• A genuine remaining battery or monitoring fault.

My questions:

1. Has anyone experienced this issue after replacing HV battery modules in a BMW G20/G21 330e?
2. What is the correct procedure to verify SME2 and CSC configuration after replacing or rearranging battery modules?
3. Is there an approved alternative diagnostic route if the ISTA procedure requires EOS validation?
4. Is the CBBRequest relevant to this SME2 issue, or is it unrelated certificate management?
5. Which SME2 live-data parameters and diagnostic logs should I collect next?

I can provide anonymised SVT Actual, SME fault reports, live data and screenshots.

I'm also open to professional paid remote diagnostic assistance, preferably from someone experienced with BMW SME2 HVS 01/02.

Any help would be greatly appreciated.

Thank you!