How to reset Mercedes Benz 48V mild hybrid battery BMS using OBDSTAR X300 Classic G3 or P003 programmer? We will explain step by step how to operate it.
Prerequisites and Tools Required:
Tools:
OBDSTAR X300 Classic G3 or P50 (for P50, additional adapters like Bench-A V3 and Bench-B V2 may be required).
T003 adapter (for battery cable and DCDC connections) and P004 adapter.
12V external power supply for the OBDSTAR device.
Multimeter (for voltage verification).
Battery Condition:
Ensure the battery voltage is above 45V. If below 45V, disassemble the battery case, disconnect the BMS module, and charge the battery to 45–47V (exceeding 48V may cause malfunctions)
Step-by-Step Reset Procedure
1. Prepare the System:
Connect the T003 adapter to the battery module, including the battery cable and DCDC cable.
Link the T003 adapter to the P004 adapter and ensure the OBDSTAR device is powered by a 12V supply.
2. Select BMS Reset Function:
Navigate to the BMS Reset menu on the OBDSTAR tool.
Choose the Benz BMS (48V) option and proceed to ECU Unlock.
3. Unlock the BMS:
Follow on-screen prompts to unlock the BMS. A successful unlock will allow access to the test platform functions.
4. Verify Voltage:
Use the multimeter to measure the BMS voltage. The reading should be ≤47V to confirm the reset is successful. Voltage exceeding 48V indicates a potential issue.
5. Test Platform Validation:
Access the Test Platform Function on the OBDSTAR device.
Select the 48V BMS option and input the vehicle model (e.g., W166, W205, W213) to finalize the reset.
Key Considerations
Battery Health:
If the battery is physically damaged or fails to hold a charge post-reset, replacement may be necessary. Resetting the BMS does not repair hardware defects.
Post-Reset Checks:
After resetting, monitor the hybrid system for errors using the OBDSTAR tool or an OBD-II scanner to ensure no fault codes persist.
Safety Precautions:
Avoid disassembling the battery unless voltage is critically low. Always wear protective gear and follow manufacturer guidelines.
