Initial Inspection and Diagnostic Overview

General Information

EuroVans from 12.00 > are equipped with Immobilizer Generation III.

Generation III has the same functionality as Generation II. However, in addition to the normal data exchange between the immobilizer control module and ignition key, Gen. III includes data exchange between the immobilizer control module and Engine Control Module (ECM).

Data exchange between the Immobilizer control module and ECM takes place either over the "W"circuit or vehicle CAN-Bus network (CAN-Bus method will be implemented as a running change during m.y. 2001 production). Confirmation of data exchange method is visible using Scan Tool function 08, Read measuring value block, Display Group 001. Measuring Value Blocks (function 08)
If a baud rate value appears in display field 1, data exchange is via the "W"circuit. If the words "Data Bus" appear in display field 1, data exchange is via the vehicle CAN Bus network.

Immobilizer functions supported by:
- a control module
- an adapted Engine Control Module (ECM)
- an induction coil at ignition lock
- adapted ignition keys with electronics (transponder/response read memory).


NOTE:
- Ignition keys for Immobilizer III are marked with "W3"! For definitive differentiation, perform Scan Tool function 02 "Check control module version". Checking Control Module Versions
- The 14-digit identification number of the control module for anti-theft immobilizer is determined with Scan Tool function 02, "Check control module version" Checking Control Module Versions


The control module for anti-theft immobilizer -J362- is located behind the instrument cluster and has On Board Diagnostic capability.

Function

Immobilizer III uses encrypted codes to increase anti-theft protection.

With encrypted codes, the control module for anti-theft immobilizer randomly generates a number and transmits it to the encryption transponder in the ignition key.

Each transponder contains its own fixed code. The transponder uses a specific algorithm to calculate a new number based on the transmitted number and the fixed code.

This new number, the "encrypted code" is sent back to the control module for anti-theft immobilizer where it is backtracked according to the same algorithm.

The backtracked number and the original, randomly generated number must match. The key is then recognized as authorized.

Following recognition of the authorized key, a variable code is transmitted to the Engine Control Module (ECM).

The variable code is randomly re-generated in the Engine Control Module (ECM) after each engine start and is stored in both control modules.

If the variable code in the control module for anti-theft immobilizer and in the Engine Control Module (ECM) match, the engine can be started/vehicle operated.

For troubleshooting, initiate On Board Diagnostic (OBD) and read out stored data using Scan Tool VAG 1551/1552 or VAS 5051 Vehicle Diagnostic Testing and Information System. Checking Control Module Versions