INFLATOR MODULES (DAB, PAB)
Both DAB (Driver airbag) and PAB (Passenger airbag) module are comprised of inflator and cushion. The initiator (A gas generator igniting device) is assembled in the inflator. When the vehicle is in a frontal crash of sufficient force to close the sensor of SRSCM, current is developed through the deployment loop. Current passing through the initiator ignites the material in the DAB and PAB module simultaneously and inflates the airbag.
When removing the air-bag module or handling a new airbag module, it should be placed with the pad top surface facing up. In this case, the twin-lock type connector lock lever should be in the lock state and care should be taken to place it so the connector will not be damaged. Do not store a steering wheel pad on top of another one. (Storing the pad with its metallic surface up may lead to a serious accident if the airbag should inflate for some reason.)
Never measure the resistance of the airbag squib. (This may cause the airbag to deploy, which is very dangerous.)
Store the air-bag module where the ambient temperature remains below 93°C (290°F), without high humidity and away from electrical noise.
When using electric welding, disconnect the airbag connectors under the steering column near the MULTI-FUNCTION SWITCH connector before starting work.
The SRS harness is wrapped in yellow tube to be discriminated from other system harness. And the shorting bar is included inside the wiring connectors of both DAB and PAB inflator side. The shorting bar shorts the current flow DAB and PAB module circuit when the connectors are disconnected. The circuits to the inflator module are shorted in this way to help prevent unwanted deployment of the airbag when serving the airbag module.
SRSCM INDEPENDENT LAMP ACTIVATION
The SRS malfunction indicator lamp (MIL) is located on the cluster giving information of SRS operating conditions by the control signals from SRSCM.
There are certain fault conditions in which the SRSCM (SRS Control Module) cannot function and thus cannot control the operation of the lamp. In these cases, the lamp is directly activated by appropriate circuitry that operates independently of the SRSCM, as follow:
Loss of ignition voltage supply to the SRSCM: lamp turned on continuously.
Loss of internal operating voltage: lamp turned on continuously.
SRSCM not connected: lamp turned on through shorting bar in wiring harness connector.
The clock spring (coil spring) consists of two current carrying coils. It is attached between the steering column and the steering wheel. It allows rotation of the steering wheel while maintaining continuous contact of the deployment loop through the inflator module.
The steering wheel must be fitted correctly to the steering column with the clock spring at the neutral position, otherwise cable disconnection and other troubles may result.
SYSTEM COMPONENT AND LAYOUT