The Airbag ECU uses information gathered from deceleration sensors usually located in the crumple zones of a vehicle. Within just 15 milliseconds of any impact, the information is already processed by the ECU, therefore it can determine if there is really a need for airbag deployment, whether they should be triggered in stages (in the case of modern multistage airbags) or whether only the seat belt limiters should come into force or not.
Airbag ECU – Airbag Electronic Control Unit
