Wrangler 4WD L4-150 2.5L VIN P MFI (1998)
Air Bag Control Module: Description and Operation
SYSTEM OPERATION
The Airbag Control Module (ACM) contains the impact sensor, and a microprocessor that monitors the impact sensor and the airbag system
electrical circuits to determine the system readiness. The ACM contains On-Board Diagnostics (OBD), and will send an airbag lamp-on message
to the instrument cluster on the Chrysler Collision Detection (CCD) data bus to light the airbag indicator lamp in the instrument cluster when a
monitored airbag system fault occurs.
The ACM also contains an energy-storage capacitor. This capacitor stores enough electrical energy to deploy the airbags for up to one second
following a battery disconnect or failure during an impact. The purpose of the capacitor is to provide airbag system protection in a severe
secondary impact, if the initial impact has damaged or disconnected the battery, but was not severe enough to deploy the airbags.
The ACM cannot be repaired and, if damaged or faulty, it must be replaced.