Windstar V6-232 3.8L (1995)
Air Bag Diagnostic Module: Description and Operation
DESCRIPTION
The air bag diagnostic monitor continually monitors all air bag system components and wiring connections for possible concerns when the ignition
switch is in RUN.
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If the air bag diagnostic monitor detects a concern in the air bag system, a Diagnostic Trouble Code (DTC) will be written to the air bag diagnostic
monitor's Non-Volatile Memory (NVM).
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This diagnostic trouble code will then be displayed on the air bag indicator lamp.
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After servicing, the diagnostic trouble code may then be cleared from NVM.
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Performing system diagnostics is the main purpose of the air bag diagnostic monitor.
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THE AIR BAG DIAGNOSTIC MONITOR DOES NOT DEPLOY THE AIR BAGS IN THE EVENT OF A COLLISION.
The crash sensors are "hard-wired" to the air bags. Thus the crash sensors determine when the air bag will be deployed.
Several important features of the air bag diagnostic monitor and its functions within the system are described below. It is necessary that these key
features and functions are well understood.
OPERATION
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The air bag diagnostic monitor illuminates the air bag indicator for approximately six seconds when the ignition switch is turned to RUN and then
turns the air bag indicator off. This indicates that the air bag indicator is operational. If the air bag indicator does not illuminate at all, stays on
continuously, or flashes at any time, then a concern has been detected by the air bag diagnostic monitor.
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Diagnostic trouble codes, if present, will begin flashing within 30 seconds after the ignition switch has been turned to RUN. This is the amount of
time it takes the air bag diagnostic monitor to perform all tests and verify system faults, if present.
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Diagnostic trouble codes are displayed as a series of flashes and pauses of the air bag indicator. Diagnostic trouble codes are two-digit numbers.
Example: A DTC 32 is displayed as follows:
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flash flash flash -- (two second pause) -- flash flash -- (five second pause)...
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Diagnostic trouble codes are prioritized numerically so that if two or more faults occur at the same time, the diagnostic trouble code with the
highest priority will be displayed.
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After the DTC is displayed five times, the air bag indicator will illuminate continuously until the ignition switch is cycled.
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The air bag diagnostic monitor incorporates Non-Volatile Memory (NVM) to store diagnostic trouble codes and retain them indefinitely. The air
bag diagnostic monitor will always flash the highest priority diagnostic trouble code stored in NVM. Diagnostic trouble codes may be cleared from
the air bag diagnostic monitor after the conditions are serviced (see Diagnostic Trouble Code Clearing procedure for details).
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The air bag diagnostic monitor distinguishes between hard and intermittent (or repaired) conditions.
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Each of these hard diagnostic trouble codes has an equivalent diagnostic trouble code which is the sum of the diagnostic trouble code number
plus 40. This equivalent diagnostic trouble code will indicate that an intermittent condition exists, or that a hard condition has been repaired.
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Only the intermittent (repaired) diagnostic trouble codes, numbers 52-85, may be cleared from the air bag diagnostic monitor. (See Diagnostic
Trouble Code Clearing procedure.)
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Example: A Diagnostic Trouble Code 32 indicates that high resistance in the driver side air bag circuit has been, and still is, present. A DTC 72
(32 + 40) indicates that high resistance in the driver side air bag circuit existed at one time, but no longer exists due to an intermittent condition, or
a repair made to the circuit. Intermittent DTCs 61-85 may not be normally displayed by the diagnostic monitor. These stored codes may be
displayed using the Air Bag Diagnostic Trouble Code Retrieval Procedure.
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If a system fault exists and the Air Bag Warning Indicator is not functioning, an audible tone will be heard indicating a need for service. The tone
is a series of five sets of five beeps. This DOES NOT indicate a diagnostic trouble code 55 or any other diagnostic trouble code. The Air Bag
Warning Indicator must be serviced before diagnostic trouble codes can be determined.
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If a fault exists that makes unwanted air bag deployment possible, the air bag diagnostic monitor will attempt to remove deployment power by
turning on a solid state switch to blow the 10A battery fuse.
WARNING: Under no circumstances substitute another fuse value for the 10a battery fuse. Any fuse other than 10a may cause
disarming failure and may result in danger to the occupants of the vehicle. Do not attempt to replace the 10a battery fuse until the air bag
system first has been deactivated.
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If the 10A battery fuse has successfully been blown by the air bag diagnostic monitor, the air bag diagnostic monitor will not attempt to blow it
again until the condition has been serviced and DTC cleared. The air bag diagnostic monitor will store both the unwanted deployment diagnostic
