Continental Automotive 5WY8404, 5WY8406, 5WY8407 User Manual

SIEMENS VDO Automotive AG SV C CE AIS LF

User Manual

of the

SIEMENS VDO

Immobiliser and remote control system

type

HMC GH

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SIEMENS VDO Automotive AG SV C CE AIS LF

FUNCTIONAL DESCRIPTION

1. System Components

The HMC GH System is a vehicle immobilisation and remote keyless entry (RKE)
system. This system consists of a body controller module (BCM), an immobiliser
antenna with corresponding transponder and a RKE transmitter.

System Operation:
The HMC GH System combines two sub-systems: an immobiliser system and a
remote keyless entry system into one system that performs the functions of both
modules. Remote keyless entry function is provided by the RF sub-system of the
BCM and the RKE transmitter. On the other hand, the immobiliser function is
provided by the LF sub-system of the BCM and the transponder located in the key.

The operation of these functions are as follows:

Immobiliser Operation
The immobiliser system is a passive immobilization system. The immobiliser
antenna uses a magnetic couple to read the transponder’s identification code. The
communication between the immobiliser and transponder is encrypted. The BCM
compares the identification code received from the transponder with the identification
codes stored in its non-volatile memory. If the identification code from the
transponder matches one of the identification codes stored in memory, the BCM
sends a “Valid Key” message and associated “rolling code” to the Engine
Management System controller. If there is no match, the module sends an “Invalid
Key” message to the Engine Management System controller. This causes the Engine
Management System to turn off the engine.

Remote keyless Entry:
The RKE transmitter transmits at 315 MHz an ASK modulated data signal to the
BCM. The RF sub-system of BCM receives this encrypted RF signal. The BCM then
decrypts the signal and broadcasts the requested remote commands to the
appropriate control modules in the vehicle through K-line bus. In general the following
functions are provided:

- Lock the car

- Unlock the car

- Unlock the trunk of the car

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