Published: 11-May-2011
Pedestrian Protection System - Pedestrian Protection System - Overview
Description and Operation
OVERVIEW
WARNING: All pyrotechnic devices are dangerous. Before performing any procedures on any pyrotechnic device, read all
information contained within the Standard Workshop Practices section of this manual.
Refer to: Standard Workshop Practices (100-00 General Information, Description and Operation).
The pedestrian protection system is designed to mitigate injuries in a pedestrian collision with the vehicle. It does this by
utilizing a pair of pyrotechnic actuators to lift the hood away from the engine, creating a cushioned impact between the
pedestrian and the vehicle.
The pedestrian protection system also includes passive protection integrated into the bumper system and bonnet structure.
WARNING: Do not fit any non-Jaguar approved accessories to the vehicle.
NOTE: The pedestrian protection system operates independently from the SRS (supplemental restraint system).
7 RH accelerometer 8 LH accelerometer 9 RJB (rear junction box) 10 BJB (battery junction box)
System Operation
The pedestrian protection system is operational when the vehicle is traveling at speeds between approximately 20 km/h (12.4
mph) and 45 km/h (28 mph). A vehicle speed signal is received by the pedestrian protection system control module over the
high speed CAN bus.
The system is able to determine if contact is made with a pedestrian or another object, such as a traffic cone, using signals
from accelerometers mounted behind the front bumper. When the system determines contact is made with a pedestrian it fires
the actuators to lift the rear of the hood approximately 130 mm within 35 ms of the 'fire' signal.
When an impact condition is registered, the pedestrian protection system control module outputs an impact signal on the high
speed CAN bus. This signal is used by the RJB to initiate the hazard warning lamps. If this occurs, the hazard warning lamp switch is disabled for the remainder of the current ignition cycle.
If the pedestrian protection system control module detects a fault with the system, it outputs a message on the high speed
CAN bus to the instrument cluster message center. On receipt of this, the message center will display the message 'CHECK PEDESTRIAN SYSTEM'.
The pedestrian protection system control module also stores the VIN (vehicle identification number). If a new control module
is fitted to the vehicle the Jaguar approved diagnostic tool must be used to program the unit with the vehicles VIN.
When the vehicle is delivered from the factory the pedestrian protection system is in a 'safe' plant mode. Normal operating
mode should be activated using the Jaguar approved diagnostic tool during the Pre-Delivery Inspection (PDI) prior to delivery
to the customer. For additional information, refer to the PDI manual.
If any damage is caused to the front of the vehicle, be it cosmetic or structural, repairs must be carried out in line with the
processes contained in the workshop manual. Failure to carry out the correct repair process could compromise operation of the
pedestrian protection system. Refer to GTR for the latest information.
The vehicle must be left for 1 minute after disconnecting the battery before any work can be carried out on the pedestrian
protection system.
Failure Mode Detection
In service, if any fault is detected, or any part of the system is recognized as not being present, the message center displays
the warning 'Check Pedestrian System'.
The bonnet deployment actuators are non-serviceable components, and if they must be replaced due to a fault, or due to
having been deployed, or following any other accident, their barcode labels must be read and recorded in the service database
against the vehicle VIN for security purposes.
After deployment of the pedestrian protection system, the vehicle must be stopped as soon as it is safe to do so. The hazard
warning lamps will be activated and can only be switched off by pressing the engine START/STOP button to turn the engine off
and on again. A warning message 'CHECK PEDESTRIAN SYSTEM' will appear on the message center and the vehicle should be
transported to the nearest dealer/authorised repairer. The vehicle must not be driven when the bonnet has been deployed.
NOTE: If the warning message 'CHECK PEDESTRIAN SYSTEM' appears in the message center when the bonnet has not
been deployed, the vehicle should be taken to the nearest dealer/authorised repairer immediately. It can be driven.
If any significant damage occurs to the front bumper it should be inspected by a dealer/authorised repairer as soon as
possible.
CONTROL MODULE Component Description
The control module is mounted below the hood release lever behind the side trim in the left hand front footwell.
The deployment signal is received from the pedestrian protection system control module. The second-generation system
adopted for XF is all-new to Jaguar and, although similar, differs from that introduced on XK by having an accelerometer-based
sensing system rather than a contact-sensing system. The accelerometer-based system is supplied by Bosch. Mounted very
close to the skin of the bumper, it examines the characteristics of vibration waves caused by impact. Its response time is
quicker, because it does not rely on the front of the bumper being loaded. It uses the 'saved' time to make more complex
decisions, and so has fewer error states. The speed of vehicle and the length of the bonnet define the time available to get
the bonnet into its deployed and stabilized position. It is possible, therefore, to create a time-line counting back from the
predicted moment of head impact to the time when the deployment signals need to be sent. That in turn defines a time from
first contact to decision time.
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