Immobilizer

Immobilizer





Introduction
Cars with ME 7.0 and Denso engine management system has a further developed immobilizer system. The greatest differences, compared to the earlier system in the X70, are:
Each engine variant has a unique MIN code. The code is fixed and is programmed into the engine control module (ECM) by the respective supplier (Bosch or Denso).
Each has a unique VIN code. The code is determined and entered into the immobilizer control module when the car is built. VIN code is also stored in the Volvo database.

Note! When replacing the Immobilizer control module the cars unique VIN codes must always be programmed in. In addition, it programs in the MIN code that the immobilizer will be receiving from the engine control module (ECM).

When the engine is switched on for the first time copies of the VIN code and MIN code are sent to the engine control module (ECM) and immobilizer control modules (ICM) respectively. The ECM then "learns" this code and is then "married" to the code.
A new code, the Immo-VGLA code which is used by the VGLA for the override function, has been developed and must be programmed into the immobilizer control module when replacing (6 digit code).

Function
Each time the ignition is switched on the engine control module (ECM) generates a random code (the code is changed every time the engine starts). The random code is sent together with the MIN code as an encrypted signal to the Immobilizer control module (ICM).
The Immobilizer control module decrypts the signal and compares the MIN code with the MIN code that it has learned. If the MIN code is correct the Immobilizer control module (ICM) generates a random code ( the code is changed for each engine start). The random code is sent together with the VIN code as an encrypted signal to the engine control module (ECM). If the MIN code is faulty the engine starts but then stops.
The Immobilizer control module decrypts the signal and compares the VIN code with the VIN code that it has learned. If the VIN code is correct the engine starts, if the code is incorrect the engine starts but then stops.
With the ignition on the key is checked to that it is an approved type, the immobilizer sends the Immo-VGLA code to the VGLA control module. This signal is used together with the override function in the VGLA system.

Note!
Points to observe when working with the ECM/ICM
- When replacing the engine control module (ECM) the VIN code must be erased before the engine control module (ECM) is removed. This is so that the engine control module (ECM) can be tested in case of guarantee claims. The VIN code is erased through the immobilizer control module (ICM) diagnostic. The car PIN code is required for erasure.
- When moving/testing the engine control module (ECM) between cars the VIN code must be erased in both car control modules. The erasing can only be carried out in the original car.

Programming
The necessary codes and software can be obtained from the Volvo database using VIDA.