7 Low frequency antenna - front 8 Low frequency antenna - center 9 Low frequency antenna - rear 10 Radio frequency receiver 11 Start control module 12 CJB (central junction box) 13 Instrument cluster 14 Megafuse (250 amp)
System Operation
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, 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 ECMit will exchange encrypted data with: The electric steering lock mechanism to authorize unlocking the steering column.
The RJB 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 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.
NOTES:
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.
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.
To ensure optimum long term reliability of the smart key the battery must be replaced with a brand new, unused battery. If a
used battery is installed the "SMART KEY BATTERY LOW" message may not be cleared. To avoid contamination of the contacts
the battery should be removed from its packaging and installed into the smart key while wearing gloves. To confirm that the
replacement battery is working correctly press the unlock button twice while holding the smart key outside the vehicle, then
enter the vehicle with the smart key, press the start button and confirm that the "SMART KEY BATTERY LOW" message is not
displayed.
Start Control Module Component Description
The start control module is used if the keyless vehicle module is unable to authorise 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.
