Air Bag Indicator

Instrument panel cluster illuminates air bag indicator when the following occurs:

• Inflatable restraint Sensing and Diagnostic Module (SDM) detects a malfunction with Supplemental Inflatable Restraint (SIR) system. Body Control Module (BCM) receives a class 2 message from SDM requesting illumination. BCM sends a message to instrument panel cluster via Serial Peripheral Interface (SPI) requesting illumination. BCM also sends a class 2 message to radio in order to activate an audible warning.
• Instrument panel cluster performs displays test at start of each ignition cycle as commanded by BCM. Instrument panel cluster flashes air bag indicator 7 times.
• Instrument panel cluster detects a loss of SPI communications with BCM.
• BCM detects a loss of class 2 communications with SDM.