Air Bag Control Module: Description and Operation

SRS Unit




The SRS is a safety device which, when used in conjunction with the seat belt, is designed to help protect the driver and front passenger in a frontal impact exceeding a certain set limit. The system consists of the SRS unit (including safing sensor and impact sensor), the cable reel, the driver's airbag and front passenger's airbag.

Operation
The main circuit in the SRS unit senses and judges the force of impact and, if necessary, ignites the inflator charges. If battery voltage is too low or power is disconnected due to the impact, the voltage regulator and the back-up power circuit respectively will keep voltage at a constant level.




For the SRS to operate:
1. The impact sensor must activate, and send electric signals to the microprocessor.
2. The microprocessor must compute the signals, and send them to the airbag inflators (and seat belt tensioners).
3. The inflators must ignite and deploy the airbags (and activate the tensioners).