CONTROL MODULE
The control module is secured with two screws to the underside of the left-hand (LH) front fender reinforcement, behind the wheelarch liner. The control module is hardwired to the other system components and is also connected to the high speed controller area network (CAN) bus. The control module receives ambient air temperature, ignition state and vehicle speed on the high speed controller area network (CAN) bus.
The control module uses signals from the PCS and the accelerometers to determine if the impact on the bumper is a pedestrian or some other object. The system will always deploy where the control module determines a pedestrian impact. The system minimizes deployment for other impacts that are similar to pedestrian impact, such as traffic cones.
PEDESTRIAN CONTACT SENSOR
| Item Number | Description |
|---|---|
| 1 | Sensor module |
| 2 | Sensor backing strip/rear cover |
| 3 | Fibre optic cable |
| 4 | Foam insert |
| 5 | Sensor front cover |
The PCS is located in a slot behind the bumper foam on the front bumper beam and is secured with a single fixing.
At the end of the sensor next to the fixing there is a PCB (printed circuit board) and fibre optic transceiver, which is connected to a fibre optic cable configured in a loop. The PCS uses this fibre optic loop to detect an impact by measuring the amount of light returned to the fibre optic transceiver. A reduction in light levels occurs when the PCS is deformed by an impact. The PCS monitors the level of light returned from the loop, if a reduction of a predetermined magnitude is measured a trigger signal will be sent to the control module.
HOOD LATCH
| Item Number | Description |
|---|---|
| 1 | Latch claw |
| 2 | Spring |
| 3 | Pyrotechnic pin |
| 4 | Latch pawl |
The hood latches are located at either side of the trailing edge of the hood. Each latch is released by a small pyrotechnic pin, which is fired in response to a signal from the control module. The pyrotechnic pin engages with the latch pawl which is holding the latch claw closed. Once the pawl is moved by the pyrotechnic pin the latch claw is released and the return spring moves the latch claw to the open position allowing the hood to move open under the pressure of the hood actuator.
Hood Latch Deployment
| Item Number | Description |
|---|---|
| A | Latched |
| B | Deployed |
| 1 | Latch pawl |
| 2 | Latch claw |
| 3 | Pyrotechnic pin |
HOOD ACTUATOR
The hood actuators are pyrotechnic air bags. The hood actuators are located just forward of the hood latches on either side of the hood. The actuators comprise a pyrotechnic device to raise the hood, a secondary hood latch mechanism and a tether sleeve. Once fired a locking device mounted on top of the actuator couples with the secondary hood latch before the air bag inflates to raise the hood. This ensures that the hood can only deploy to a pre-determined height (approximately 130 mm (5.1 in.)). As the hood actuator is fired two prongs located in the secondary latch housing are moved out of their retaining clamp. The prongs are spring loaded to grip the secondary hood latch striker securing it to the actuator tether cone.
Hood Actuator and Secondary Latch
| Item Number | Description |
|---|---|
| 1 | Secondary hood latch striker plate |
| 2 | Secondary hood latch body |
| 3 | Secondary hood latch |
| 4 | Secondary hood latch spring |
| 5 | Secondary hood latch retaining bracket |
| 6 | Electrical connector |
| 7 | Hood actuator assembly |
ACCELEROMETER
Two accelerometers are mounted on the rear of the bumper beam. The accelerometers measure the amount of inertia when an impact occurs and send a signal to the control module. This signal is used by the control module to calculate the firing of the pedestrian protection system. The accelerometers are modified crash sensors. The sensors have a lower detection range than front/side crash sensors to enable them to detect lower level impacts and therefore assist in the object discrimination process.
CONTROL DIAGRAM
Note. A = Hardwired; D = High speed controller area network (CAN) bus
Scheme 9
| Item Number | Description |
|---|---|
| 1 | ABS (anti-lock brake system) module |
| 2 | ECM (engine control module) |
| 3 | Diagnostic socket |
| 4 | AJB (auxiliary junction box) |
| 5 | Hood latch |
| 6 | Accelerometer |
| 7 | Hood actuator |
| 8 | Accelerometer |
| 9 | PCS |
| 10 | Hood actuator |
| 11 | Hood latch |
| 12 | Pedestrian protection system control module |
SAFETY INFORMATION
| WARNING | To avoid accidental deployment the back-up power supply must be depleted before beginning any work on the pedestrian protection system or its components. Failure to follow this instruction may result in personal injury. |
| WARNING | Do not use a multimeter to probe the pedestrian protection system actuators. It is possible for the power from the multimeter battery to trigger the activation of the actuator. Failure to follow this instruction may result in personal injury. |
Note. It is advisable not to use a cellular phone or to have a cellular phone in close proximity when working on the pedestrian protection system or components
Note. Given the legal implications of a restraints system failure, harness repairs to pedestrian protection system circuits are not acceptable. Where the text refers to "REPAIR the circuit", this will normally mean the replacement of a harness.
Power Supply Depletion
Before beginning any work on the pedestrian protection system or related components
- Remove the ignition key.
- Disconnect the battery leads, ground first.
- Wait 2 minutes for the power circuit to discharge.
There are comprehensive instructions on the correct procedures for pedestrian protection system repairs in the manual. Refer to the relevant section of the service information.