Air Bag Control Module: Description and Operation

The diagnostic module (DM), is mounted below the passenger side air bag behind the console fascia panel. It is the electronic microprocessor that monitors the airbag system. The state of the three system sensors, two air bag modules and the wiring harness is monitored continuously to detect activation criteria and component faults.

The module also confirms correct supply conditions by comparing a direct battery voltage input, with an ignition switched input, of the same voltage value. Detection of system faults are relayed by the module to the instrument panel to illuminate the AIR BAG MIL.

The module contains a reserve power supply unit, enabling the air bags to fire even if the supply voltage is lost during an impact situation. The reserve power charge is retained for approximately one minute after the supply voltage is disconnected.