S60 L5-2.4L VIN 64 B5244S6 (2003)
Impact Sensor: Description and Operation
Introduction, Sensors
Side collision sensors
The sensors for side impact detection are located on the of the B and C posts. This location allows quick (early) reaction time in the event of side impact.
The sensors on the B and C-posts are not interchangeable/identical. The B-post sensor is gray and the C-post sensor is black (different collision
parameters).
The sensors are directly connected to the SRS module.
The side impact sensors are "independent units". The sensor is made up of a micro processor with an acceleration sensor and interface.
The side impact sensor spontaneously carries out internal diagnoses and registers with the SRS unit that the sensor is fault free.
The side impact sensor registers with the SRS unit if a collision impulse is detected with sufficiently high energy content. The SRS unit then checks
whether it also senses the collision impulse, in which case it triggers the safety equipment. It is the SRS module that determines if, when and which safety
equipment should be deployed.
SRS module
The SRS unit continually transmits diagnostic pulses to all SRS components. The diagnostic pulses check that there are no wiring short-circuits or other
faults in the SRS system. In the event of a fault the SRS lamp lights. (The SRS lamp also lights briefly (approximately 7 s) when the ignition is switched
on. During this time the SRS module starts up the side impact sensors, runs self diagnostics and diagnostics of other SRS components and charges the
SRS system's ignition capacitor).
The bracket for the module must be rigidly secured in the body and welded (with as high resonance frequency as possible greater than 300 Hz).
