June 01, 2026

How to Solve OBDSTAR G3 Failed to Decode Skoda EDC17C74 CS Code

Here comes a problem:

It’s a 2017 Skoda MQB model with an EDC17C74 ECU. All keys have lost. A customer was trying to make key withOBDSTAR X300 Classic G3programmer on bench.

He connected the ECU to the G3 on bench and read the EEPROM successfully, but the strange thing is that he can also read the FLASH successfully, but when it reads the sectors, it goes super fast, and the BLUE LED on the MP001 barely flashes to indicate communication with the ECU. It’s like the ECU is being read incorrectly, and when he used the special "decrypt immo data” option, the CS is really strange.

 

OBDSTAR G3 Failed to Decode Skoda EDC17C74 CS Code 1

OBDSTAR G3 Failed to Decode Skoda EDC17C74 CS Code 2

 

Here is the clue.

Edc17C74 and CP74 are Immo 6 and have the SHE sector.It reads ok, but these ECUs have SHE sector security hardware extension. No tool in the world can decrypt it and no way to decode it. You cannot read CS code.

 

What is IMMO6 SHE?

IMMO6(or WFS6) refers to the 6th generation of theVolkswagen/Audi Group (VAG) immobilizer system, whileSHEstands for Secure Hardware Extension—a hardware-based security layer used in modern ECUs. Part of immo data is stored not in eeprom but in SHE – which you can’t read.

The SHE (Secure Extension Hardware) module implements advanced AES-128 encryption and dynamic challenge-response authentication, making it highly resistant to hacking or unauthorized ECU cloning.

 

 

How to Program MQB All Keys Lost with IMMO6 SHE ECU?

Solution 1:

Order dealer key for 120€ and program with online software ODIS.

 

Solution 2:

Order dealer key and use mlb tool to add key.

For example:

Use the dealer key to read immo then leave dealer key with CS code. Key already has sync then you can make more keys if you want.

Order a dealer key, read immo data on the dealer key withVVDI MLB Tool (MQB adapter)orKD-MP tool, and make dealer key and learn keys.

 

Solution 3:

Make ecu immo off, and when add on calculation time another car cs code to fill the sync calculation and make key and oem ecu immo off.

Posted by: jean at 06:40 AM | No Comments | Add Comment
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