In this guide, we walk through the complete process of Repairing a Mercedes TCM (VGS4) using OBDSTAR G3 and supporting adapters.
What You’ll Need
KeyMaster G3
OBDSTAR C4-07 toolkit (for access drilling)
W011 harness
MP001 programmer
Dedicated TCM cable
Stable external power supply
Important Preparation
To access the internal communication points of the TCM (VGS4), you need to drill a precise hole according to the official diagram using the C4-07 toolkit.
Once drilling is completed:
Connect the C4-007-01 adapter to the gearbox module
Link the W011 harness between the adapter and MP001
Attach the dedicated TCM cable
Ensure a stable external power supply
Step 1: Data Backup
Start by backing up the original data from the module.
Open ECU Flasher on X300 Classic G3 Select TCM ->> Search for VGS4 and choose the first option ->> Select JTAG mode ->> Confirm connection when prompted
Once connected:
Click ECU Info to verify communication (VIN should appear)
Tap Connect → Read Data
Save the file (keep the default name for safety)
This backup file is critical for restoring the module later.
Step 2: Perform Reset (Virginizing)
Next, reset the used TCM to a “virgin” state.
Select the reset/virginizing function
Allow the tool to complete the process
After completion:
VIN and coding data will be cleared
Module is now ready for reprogramming
Step 3: Write Data Back
You have two options depending on your situation:
Method 1: Write Original Data Back
If you have the backup file:
Go to Data Transfer
Load the saved file
Write data into the used module
Once successful, the module can be reinstalled and should work normally.
Method 2: Online Programming (Without Backup File)
If no original data is available:
Use official Mercedes diagnostic tools
Perform online programming after virginizing
Sync the module with the vehicle
Final Step: Installation & Testing
Reinstall the TCM into the vehicle
Start the car and verify operation
If all steps are done correctly, the vehicle should start and drive normally.
Final Tip
After completing the procedure, seal the drilled hole with glue to prevent:
Moisture intrusion
Dust contamination
Future module damage
OBDSTAR X300 Classic G3 repairs a Mercedes TCM (VGS4) becomes a practical and cost-effective solution. By following proper steps—backup, reset, and data writing—you can successfully reuse used modules and save significantly on replacement costs.
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