Description

Anti-Theft - Passive

NOTE:
A = Hardwired; D = High speed CAN; N = Medium speed CAN; O = LIN bus










The passive start function prevents the vehicle from being started by unauthorized persons. It does this by immobilizing the ignition, fuel and engine crank functions. The system is automatic and requires no input from the driver.
At the request of the CJB (central junction box), the keyless vehicle module prompts each of the Low Frequency (LF) antennae to output a signal. When the Smart Key is in the vehicle cabin, it detects the LF signals and responds with a Radio Frequency (RF) data-identification signal back to the keyless vehicle module via the RF receiver.
If the data received matches that stored in the keyless vehicle module it continues the passive start process by communicating a 'Smart Key valid' signal to the CJB via the medium speed CAN (controller area network) bus.
Once the CJB receives the authorization and confirms a response with an internal calculation, it passes the result to the instrument cluster on the medium speed CAN bus.
Before the instrument cluster sends a mobilization signal to the ECM (engine control module)it will exchange encrypted data with:
- The electric steering lock mechanism to authorize unlocking the steering column.
- The RJB (rear junction box) to authorize fuel pump operation. Once the RJB receives the authorization and confirms the response with an internal calculation, it will enable the FPDM (fuel pump driver module).
- The CJB to authorize the ignition status. If the drive selector is in the park position and the driver presses the brake pedal and simultaneously presses the start/stop switch, the CJB interprets this as an engine crank request. Before the engine crank request is allowed, the CJB compares a brake pressure signal received from the ABS (anti-lock brake system) module. The brake pressure signal is compared to an internally stored threshold value within the CJB. If the signal is greater than the stored threshold value, a crank request signal is sent to the ECM on the high speed CAN bus.
Once these factors have been confirmed, and the vehicle is in 'Park', the engine can be started by pressing the brake pedal and the Stop/Start button simultaneously.

NOTE:
If the keyless vehicle module fails to locate the Smart Key, the message 'SMART KEY NOT FOUND PLEASE INSERT IN SLOT' will appear in the instrument cluster message center. When inserted the start control module will read the transponder within the Smart Key. If the transponder identification is valid, authorization will be transmitted to the instrument cluster on the LIN (local interconnect network) bus.

NOTE:
When the vehicle is delivered from the factory the passive start function is inhibited. In this condition the vehicle can only be started by placing the Smart Key in the start control module. The system should be switched on during the Pre-Delivery Inspection (PDI) using the Jaguar approved diagnostic system. For additional information, refer to the PDI Manual.

Start Control Module
The start control module is used if the keyless vehicle module is unable to authorize the Smart Key.
If the keyless vehicle module 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 in the conventional manner. The driver will be alerted to this by a chime and a message in the instrument cluster message center 'SMART KEY NOT FOUND PLEASE INSERT IN SLOT'.
Once inserted the start control module will read the transponder within the Smart Key. If the transponder identification is valid, authorization will be transmitted to the instrument cluster on the LIN bus.

NOTE:
Inserting the Smart Key into the start control module will not charge the Smart Key battery. The battery is non-chargeable and must be replaced if defective.
A message 'REMOVE SMART KEY' will be displayed if the Smart Key is still in the start control module and the driver's door is opened.

Low Frequency Antenna
Three Low Frequency (LF) antennae for the passive start system are positioned in specific locations in the vehicle; refer to Component Location graphic.

NOTE:
On vehicles with the passive entry system, five additional antennae are used; one integrated into the rear bumper and one in each door handle assembly. These are only used by the passive entry system and have no function in the passive start system. For additional information, refer to Anti-Theft - Active Description
The keyless vehicle module transmits an LF signal via the antennae which is received by the Smart Key. The Smart Key then responds by transmitting a Radio Frequency (RF) signal which is received by the RF receiver and passed to the keyless vehicle module for authorization.

Keyless Vehicle Module
The keyless vehicle module controls 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 connection to the CJB for authorizing vehicle starting.

Radio Frequency Receiver
The Radio Frequency (RF) receiver transmission is received from the Smart Key to enable key identification.