Mystique L4-122 2.0L DOHC VIN 3 SFI (1995)
Air Bag Control Module: Description and Operation
Air Bag Diagnostic Monitor
The air bag diagnostic monitor:
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Continually monitors all air bag system components and wiring connections for possible faults in the system.
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Displays a Diagnostic Trouble Code (DTC) by flashing the air bag warning indicator if it detects a fault in the air bag system when the ignition
switch is in RUN.
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Performs system diagnostics, which is its main purpose.
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THE DIAGNOSTIC MONITOR DOES NOT DEPLOY THE AIR BAGS IN THE EVENT OF A CRASH! The crash sensors are "hard wired" to
the air bags, and therefore the crash sensors determine when to deploy the air bags.
Air Bag System Functions
Several important features of the air bag diagnostic monitor and its functions within the system are described below. It is necessary that you
understand these key features and functions. They will enable you to understand and perform efficient air bag system diagnostics.
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The air bag diagnostic monitor illuminates the air bag warning indicator for approximately six seconds when the ignition switch is turned to RUN
and then turns it off. This indicates that the air bag warning indicator is operational. If the air bag warning indicator does not illuminate or if the air
bag warning indicator stays on or flashes at any time, a fault has been detected by the air bag diagnostic monitor.
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Diagnostic trouble codes may not be displayed for approximately 45 seconds after the ignition switch has been switched to RUN. This is the
amount of time it takes the air bag diagnostic monitor to perform all tests and verify any system faults.
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Diagnostic trouble codes are displayed as a series of flashes and pauses of the air bag warning indicator. Each diagnostic trouble code, or series of
flashes, represents a two- digit number. For example, a Diagnostic Trouble Code 32 is displayed as follows:
flash flash flash - (one-second pause) - flash flash - (three-second pause)...
flash flash flash - (one-second pause) - flash flash - (three-second pause)...
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If a system fault exists and the air bag warning indicator is malfunctioning, an audible tone will be heard indicating the need for service. The tone
is a series of five sets of five beeps. This DOES NOT indicate a diagnostic trouble code 55 It means that the air bag warning indicator is out and a
system fault exists that requires service.
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If a fault exists that makes unwanted air bag deployment possible, the air bag diagnostic monitor has an internal thermal fuse that will blow
automatically. This removes all power to the air bag deployment circuit. The air bag warning indicator will flash the appropriate code to indicate
the suspect circuit. The thermal fuse does not blow because of excessive current flowing through it. DO NOT attempt to short circuit the thermal
fuse with a circuit breaker of any other type of fuse. The thermal fuse is controlled by the air bag diagnostic monitor and is not serviceable.
