Engine control module can be damaged after accident or soaking, sometimes cannot be repaired and can only be replaced. For VW and Audi models, Bosch MED17.5.X, MED17.5.20, MED17.1.x are widely used in Passat, Magotan CC, Tiguan, Golf 6, Sagitar, Audi Q5 and other models. If replace a new Bosch MED17, only need to do online coding with special diagnose software. If replace a used one, need to modify VIN. In this post we will show one method on modify VIN for Bosch MED17, here we take a Golf 6 Bosch MED17.5.20 as an example.


Step 1: Read EEPROM data of used Bosch MED17.5.20 with key programmer like Ktag or Dimsport.

Here we use Ktag to display. Start Ktag software, choose P179 protocol, and click “direct connection” to see the wiring diagram, as per diagram to read the data and save the EPR file, also backup this file.



Step 2: Modify VIN in EPR file.

Open the EPR file in HEX Workshop, there are 4 VIN codes in this file, replace all of them with original car’s VIN and save the date. It should be noted this Bosch MED17.5.20 has 4 vin codes in EEPROM data, but some other type ECM have one to four VIN code in data that must be all replaced.


Step 3: Do checksum Correction for VIN.

After the original car’s VIN wrote into EEPROM data, need to do checksum correction. We can use software IMMOFF 17 to do checksum correction (Software order and download in the official website:,). In the IMMOFF software, choose “EEPROM * Checksum correction only”, then load the EPR file read in step 1, sooner require to load modified EPR file in step 2, after loading, the software will start to do checksum and generate a new EPR file with name “checksum-ok” in same file folder.

Step 4: Write checksum-ok EPR file to Bosch MED17.5.20.

Go back to Ktag software, write checksum-ok EPR file to ECM MED17.5.20, then the VIN code modification complete.


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