Electrical System Description

The SRS airbag system has sophisticate electrical and electronic components, therefore the airbag operating components should be handled very carefully.

SRSCM (Supplemental Restraint System Control Module)
SRSCM determines to deploy the airbag module by sensing the frontal and side impact sensed by the sensor built in SRSCM.

DC/DC Convertor
The DC/DC convertors of the power supply includes a step up and a step down converter, which provides the firing voltage for two firing circuits and the internal operating voltage. If the internal operating voltage falls below a defined threshold a reset is executed.

Arming Sensor/Safing Sensor
The arming/safing sensor built in the airbag firing circuit has the function of arming the airbag circuit under all required deployment condition and maintaining the airbag firing circuits unarmed under normal driving conditions. The safing sensor is a dual-contact electromechanical switch which closes if it experiences a deceleration exceeding a specified threshold.

Back-Up Power
The SRSCM reserves the energy supply to provide deployment energy for a short second when the vehicle voltage is low or if lost in a vehicle frontal crash.

Malfunction Detection
The SRSCM continuously monitors the current SRS operation status while the ignition key is turned on and detects the malfunction of the system. The malfunction can be displayed in the form of diagnostic trouble code using Scan tool.

MIL (Malfunction Indication Lamp) Notification
If any fault is detected, the SRSCM sends signal to the indicator lamp on the cluster to warn the vehicle driver. The MIL indicator is the key to driver notification of SRS faults. Verify lamp and SRSCM operation by flashing 6 times when the ignition switch is first turned on.

Malfunction Recording
Once a fault occurred in the system SRSCM records the fault in the memory in the form of DTC and the DTC is erased only by Scan tool.

Data Link Connector
The SRSCM memory stored data are linked through this connector located at the underneath of driver side crash pad to the external output device such as Scan tool.

After firing the airbags once, the SRSCM cannot be used again and must be replaced.