Anti-Theft - Passive
Anti-Theft - Passive
COMPONENT LOCATIONS
NOTE:
RHD installation shown, LHD installation similar
OVERVIEW
The passive anti-theft system provides a secure interface between the CJB (central junction box) and the ECM (engine control module), to prevent unauthorized starting of the vehicle. Unauthorized starting prevention is achieved by immobilization of the engine crank system and the fuel system.
The passive anti-theft system is a function of the 'Passive Start' system. The system uses the following components:
- Smart key
- Low Frequency (LF) antennas (5 off)
- Radio Frequency (RF) receiver
- Keyless Vehicle Module (KVM)
- Immobilizer Antenna Unit (IAU)
- CJB (central junction box)
- ECM (engine control module).
The system is automatic and requires no input from the driver other than to press the brake pedal and the start/stop button. The engine management system will only allow engine crank and fuelling when an authorization data message is received from the CJB (central junction box).
Engine starting is prevented by inhibiting the fuel, engine (spark, injectors and crank) and ignition systems from operating. This is achieved by using a uniquely coded Smart Key and an encoded data exchange between multiple control modules.
The engine start system is initiated when the encoded data between the Smart Key and KVM and CJB (central junction box) and ECM (engine control module) is verified. The engine can then be started when the drive selector is in the 'Park' position, and the start/stop button and the brake pedal are pressed simultaneously.
SYSTEM OPERATION
Passive Start System
At the request of the CJB (central junction box), the KVM prompts each of the LF antennas to output a signal. When the Smart Key is in the vehicle cabin, it detects the LF signals and responds with a RF data-identification signal back to the KVM via the RF receiver.
If the data received matches that stored in the KVM it continues the passive start process by communicating a 'Smart Key valid' signal to the CJB (central junction box) via the medium speed CAN (controller area network) bus.
Once the CJB (central junction box) receives the authorization and confirms the response with an internal calculation, it passes coded data to the ECM (engine control module) on the high speed CAN (controller area network) bus. Upon confirmation from the ECM (engine control module) the ignition is enabled.
Before the CJB (central junction box) sends a mobilization signal to the ECM (engine control module) it will exchange encrypted data with the electric steering lock and the instrument cluster to authorize unlocking of the steering column. The instrument cluster only provides a ground for the steering lock motor.
The CJB (central junction box) will enable the fuel pump relay which, on diesel vehicles operates the fuel pump and on gasoline vehicles sends a battery voltage supply to the FPDM (fuel pump driver module) to operate the fuel pump in conjunction with the ECM (engine control module).
If the transmission selector is in the park position and the driver presses the brake pedal and simultaneously presses the start/stop button, the CJB (central junction box) interprets this as an engine crank request. Before the engine crank request is allowed, the CJB (central junction box) compares a brake pressure signal received from the ABS (anti-lock brake system) module. If the signal is greater than the stored threshold value, a crank request signal is sent to the ECM (engine control module) on the high speed CAN (controller area network) bus.
NOTE:
If the KVM fails to locate the Smart Key, a message 'SMART KEY NOT FOUND REFER TO HANDBOOK' will appear in the instrument cluster message center and the keyless start back-up process will have to be used to mobilize and start the vehicle.
Keyless Start Back-up
If the vehicle has been unlocked using the emergency key blade or the Smart Key is not detected by the vehicle, it will be necessary to use the keyless start back-up system to disarm the alarm and start the engine. The following process must be followed in this event:
- Position the Smart Key against the underside of the instrument panel, on the outboard side of the steering column, with the buttons facing downwards. This is the location of the IAU.
- Holding the Smart Key in position and with the brake pedal depressed, press the start/stop button to start the engine.
Position of Smart Key on instrument panel.
NOTE:
LHD (left-hand drive) shown RHD (right-hand drive) similar.
This process bypasses the data exchange between the KVM and the CJB (central junction box). A transponder within the Smart Key is detected by the IAU. The IAU confirms the code output from the transponder and communicates this code confirmation with the CJB (central junction box) via a LIN (local interconnect network) bus connection. The CJB (central junction box) then initiates the vehicle start process in the normal manner.
COMPONENT DESCRIPTION
Immobilizer Antenna Unit (IAU)
NOTE:
RHD (right-hand drive) shown LHD (left-hand drive) similar.
The IAU is located on the underside of the instrument panel, outboard of the steering column, below the footwell lamp. The IAU cannot be seen as it is located behind the trim panel. The IAU is used if the KVM is unable to authorize the Smart Key. The driver will be alerted to this by a chime and a message in the instrument cluster message center 'SMART KEY NOT FOUND REFER TO HANDBOOK'.
If the KVM is unable to identify the Smart Key, for example if the Smart Key battery voltage is low or there is local RF interference, the transponder within the Smart Key can be read by holding the smart key against then instrument panel in the position shown in the illustration.
Low Frequency (LF) Antennas
Five Low Frequency (LF) antennas for the passive start system are positioned in specific locations within the vehicle.
The KVM transmits an LF signal via the antennas which is received by the Smart Key. The Smart Key then responds by transmitting a RF signal which is received by the RF receiver and passed to the KVM for authorization.
Keyless Vehicle Module (KVM)
The KVM is located in the LH (left-hand) side of the luggage compartment, behind the trim panel and receives a power supply from the CJB (central junction box). A serial communication line from the KVM to the RF receiver (which is located behind the headlining, rearward of the sunroof), transmits coded data from the Smart Key to the KVM for vehicle locking and unlocking using the Smart Key buttons.
The KVM controls LF signal transmissions to and from the Smart Key and provides authorization to allow the vehicle to be started. The module has a medium speed CAN (controller area network) bus connection to the CJB (central junction box) for authorizing vehicle starting.
Control Diagram
NOTE:
A = Hardwired; D = High speed CAN bus; F = RF transmission; N = Medium speed CAN bus; O = LIN bus; AH = Serial communication line
