C Yukon 2WD V8-5.7L VIN R (1999)
Air Bag Check Indicator: Description and Operation
The ignition switch applies ignition voltage to the AIR BAG warning lamp. The AIR BAG warning lamp receives power whenever the ignition switch is
at the RUN or START positions. The Inflatable Restraint Sensing and Diagnostic Module (SDM) controls the lamp by providing ground with a lamp
driver. The SIR system uses the AIR BAG warning lamp to perform the following steps:
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Verify lamp and SDM operation by flashing the lamp 7 times when the ignition switch is first turned to the RUN position.
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Warn the vehicle driver of SIR electrical system malfunctions which could potentially affect the operation of the SIR system. These
malfunctions could result in either of the following conditions:
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Non-deployment in the case of a frontal crash
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Deployment for conditions less severe than intended
The AIR BAG warning lamp is the key to driver notification of SIR system malfunctions. Refer to SIR Diagnostic System Check for proper lamp
operation.