MQB48 vehicles (VW, Audi, Seat, Skoda) use BCM2 as the immobiliser brain. Understanding EEPROM layout is essential for add key, AKL, IMMO extraction, BCM2 recovery, and key authorization logic.
This extended guide breaks down BCM2 EEPROM structure in detail.
BCM2 EEPROM Map (Extended Cheatcode Section)
Region | Function |
|---|---|
0x0000–0x00FF | Boot |
0x0100–0x03FF | CS (Component Security) |
0x0400–0x07FF | IMMO data |
0x0800–0x0BFF | Sync bytes |
0x0C00–0x0FFF | Key authorization |
0x1000–0x13FF | Error memory |
0x1400–0x17FF | Rolling code blocks |
0x1800–0x1FFF | Backup region |
Data Breakdown
CS (Component Security)
Defines immobiliser identity
Must match ECU + cluster
Required for key generation
IMMO Data
Vehicle identity
Used for AKL
Required for key authorization
Sync Bytes
Authorise keys
Used during add key
Critical for MQB48
Key Authorization
Determines which keys are valid
Required for AKL
Must match CS + IMMO
Rolling Codes
Prevent replay attacks
Reset during AKL
🔧 Add Key vs AKL Table
Procedure | Required Reads | Data Needed | Risk |
|---|---|---|---|
Add Key | BCM2 partial + cluster | CS, IMMO, sync | Low |
AKL | BCM2 full + cluster full + ECU | Full CS, IMMO, sync, authorization | High |
⚠️ Corruption Patterns
Common MQB48 BCM2 Faults
CS block corruption
IMMO block mismatch
Sync byte misalignment
Key authorization block corruption
Rolling code lockout
