The gas generator comprises an initiator and propellant grain housed in a metallic container. When the airbag sensor comes on, current will be applied to the initiator and ignites it.
Immediately thereafter, ignition will be transmitted to the propellant grain in an extremely short time, emitting high-pressure gas.
The initiator is ignited by even a weak current. As it is dangerous, never measure the resistance of the initiator with a volt/ohmmeter, etc.
1.M-type seat belt pretensioners component
Gas generator with pretensioner sensor
There used to be a gas generator with pretensioner sensor for M-type.
Gas generator (M-type) is composed of a mass weight that detects deceleration force, a firing pin that ignites the initiator, and so forth.
The conditions for activation of the pretensioner are the same as for the airbag system.
In order to prevent unintended deployment when removing the seat belt, or when handling the seat belt pretensioners by itself, the seat belt pretensioners is equipped with a safety device that stops the operation of the sensor.
The method by which the safety device is activated or deactivated varies according to the model. Make sure to activate and deactivate the safety device in accordance with the instructions contained in the Repair Manual or on the caution label affixed to the pretensioner.