need immo off audi simo8.5

Gringos said:

need immo off for simos 8.5 audi a8 2013
thanks

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Hello,

For Simos 8.5, a simple "immo off" solution via file patching is generally not possible or does not work correctly. This generation of ECU requires proper adaptation.

Since this is a 2013 Audi A8, the immobilizer system is stored in the BCM2.

• If you are replacing a bad ECU: You need to transfer the Immo data (CS, MAC, PIN, PowerClass) from the original ECU to the donor.
• If the original ECU is dead/missing: You need to read the BCM2 data to adapt the donor ECU.

Please upload your Full Backup (Flash + EEPROM). If you have the original ECU read, upload that as well. We might be able to help you transfer the data to make the car start.

i have the old ecu and i try to transfert data but vin number does not appear in diagnosis tool

Gringos said:

i have the old ecu and i try to transfert data but vin number does not appear in diagnosis tool

Click to expand...

If the VIN is not showing up, it usually means the EEPROM checksum is invalid or the data structure was corrupted during your transfer attempt.

Please compress and attach the following files here:

• Original ECU (Full Read: Flash + EEPROM)
• Donor ECU (Full Read: Flash + EEPROM)

I will manually transfer the CS, MAC, PIN, and VIN from the original to the donor file and correct the checksums for you. Do not try to write the bad file again until it is fixed.

this is file

Gringos said:

this is file

Click to expand...

You forgot to attach the files. Please try again, preferably compressed in a .zip or .rar archive.

Regarding your issue:
The Simos 8.5 EEPROM is checksum protected. If you manually copy-pasted the VIN or Immo data in a hex editor without recalculating the checksums (CRC), the ECU will detect the file corruption.

When the EEPROM checksum is invalid, the ECU often enters a "safe" mode or bootloader mode where it will not display the VIN or allow the engine to start.

• Upload both the Original and Donor EEPROM reads.
• If you have the Flash reads, include them as well (sometimes needed for checksum calculation).

Once you upload them, I can generate the correct file for you.

this eeprom orignal and eeprom donor

Gringos said:

this eeprom orignal and eeprom donor

Click to expand...

I still do not see any files attached to your post. Please check if the upload finished or try uploading to an external site (like Mega, Google Drive, or Sendspace) and post the link here.

While you are uploading, here is some advice on why your previous attempt failed:

• Checksum (CRC): Simos 8.5 EEPROM is protected. If you copy the Immo block (CS, MAC, PIN) manually in a Hex editor without recalculating the checksum for that block, the ECU will reject the data. This is why you see no VIN and the car won't start.
• OTP Areas: Some areas of the EEPROM might be One-Time Programmable or linked to the specific hardware ID. You should not copy the entire file. You only need to transfer the specific Immo data.

The correct procedure without manual Hex editing:
If you have tools like VVDI2, Autel IM608, or AVDI, do not use a Hex editor.

1. Open the tool's "Dump Tool" or "ECU Adapter" software.
2. Select Siemens/Continental Simos 8.5.
3. Load your Original EEPROM.
4. Read/Decrypted Immo Data (CS, PIN, MAC).
5. Load your Donor EEPROM.
6. Write the Immo Data from the Original into the Donor file.
7. Save the new file.

The tool will automatically calculate the correct checksums.

If you don't have these tools, please upload the files again properly, and I will transfer the data and fix the checksum for you.