Electronic sensors are incorporated into the RCM; these measure the vehicle acceleration/deceleration in the event of a collision. The calculated value is evaluated by the RCM to determine the severity of the impact.
The RCM compares the values it receives from the crash sensor, side impact sensors and the internal electronic sensors. If the deceleration, due to a frontal or side impact, exceeds the stored value the RCM will trigger the air bag modules and the safety belt pretensioners as required.
If the vehicle battery is destroyed in the collision, a voltage hold circuit in the RCM will still enable the air bag modules to be triggered up to 150 ms after the start of the impact.
If a system fault is detected by the RCM, the air bag warning lamp is illuminated. The fault can be located by carrying out a diagnostics check using the diagnostic tool.
The RCM can be used again after a collision, provided the RCM is not physically damaged and it passes a self-test.
Crash Sensor
The crash sensor is installed at the front of the vehicle, behind the radiator grille. Data from the crash sensor is evaluated by the RCM to assess the severity of a frontal impact. The crash sensor transmits digitally encoded acceleration information to the RCM.
Power is supplied to the crash sensor by the RCM. If a crash sensor fails, the RCM stores a Diagnostic Trouble Code (DTC).
Continued use of the crash sensor is permissible provided it has not been physically damaged and it passes a self-test.
The external shape of the crash sensor prevents it from being installed incorrectly.
Side Impact Sensors
The side impact sensors are located at the bottom of the B-pillars and transmit digitally encoded acceleration information to the RCM.
Continued use of the side impact sensor is permissible provided it has not been physically damaged and it passes a self-test.
Driver Air Bag Module, Driver Lower Air Bag Module and Passenger Air Bag Module
The driver, driver lower and passenger air bag modules are all single-stage air bags.
When the ignition is switched on, a warning lamp in the instrument panel indicates to the driver and passenger that the passenger air bag module has been deactivated.
After installing a PAD switch kit, the RCM must be re-configured using the diagnostic tool.
Side Air Curtains
The side air curtain modules are located in the roof rail between the A-pillar and C-pillar. They are attached to the upper part of the side panel and are hidden behind the vehicle trim panels.
In the event of a side impact the relevant side air curtain is deployed and forms a protective cushion between the corresponding side window and the head of the person(s) sat on the front and rear seat.
The side air curtains are deployed simultaneously with the side air bags.
Side Air Bag
The side air bags are incorporated in the front seat backrests; a sewn-on label on the respective backrest indicates the vehicle is equipped with side air bag modules.
When a side air bag is deployed, the seam of the seat cover tears open enabling the side air bag to inflate unhindered from the front seat backrest.
Safety Belt Retractor and Pretensioners
The pyrotechnic pretensioners for the driver and front passenger safety belts are incorporated into the safety belt retractors.
