SRSCM (Supplement Restraint System Control Module) decides to deploy the airbag module by sensing the frontal impact sensed by the sensor built in to the 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 four firing circuits and the internal operating voltage. If the internal operatingvoltage falls below a defined threshold, a reset is executed.
Arming sensor/safing sensor : The arming/safing sensor built in to the airbag firing circuit has the function of arming the airbag circuit under all required deployment conditions 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 exceedinga specified threshold.
Back-up power : The SRSCM reserves an energy supply to provide deployment energy for a short second when the vehicle voltage is low or if lost in avehicle frontal crash.
Malfunction detection : The SRSCM continuously monitors the current SRS operation status while the ignition key is turned on and detects possible malfunction of the system. The malfunction can be displayed in the form of a diagnostic trouble code using Hi-Scan.
MIL (Malfunction Indication Lamp) notification : If any fault is detected, the SRSCM sends a signal to the indicator lamp on the cluster to warn thevehicle driver.The MIL indicator is the key item in notifying the driver of SRS faults. Verify lamp and SRSCM operation by flashing 6 times when the ignition switchis first turned on.
Malfunction recording : Once a fault occurs in the system, the SRSCM records the fault in the memory in the form of DTC and the DTC can only beerased only by Hi-Scan.
Data link connector : Data stored in he SRSCM memory is read by Hi-Scan through the data link connector.
After firing the airbags once, the SRSCM cannot be used again and must be replaced.
Crash output : The crash output is used to control an external device which will unlock the doors in case of a crash event. The crash output is specified as follows : 0-200 µA in OFF mode and 200mA in ON mode. In case of the unlock commandthe switch is closed for 200 mS.
When the frontal Crash recorded in the SRS Control module .
Item
Detecting Condition
Possible cause
DTC Strategy
? Frontal crash recorded in the SRSCM
? Faulty SRSCM.
Enable Conditions
? Ignition "ON"
Threshold Value
? Crash recorded in the SRSCM
Diagnostic Time
Qualification
? More than 2 sec remaining
De-Qualification
? More than10 sec remaining