Milan L4-2.3L VIN Z (2006)
Air Bag Control Module: Description and Operation
RESTRAINTS CONTROL MODULE (RCM)
WARNING: The restraints control module (RCM) orientation is critical for correct system operation. If a vehicle equipped with an air bag
supplemental restraint system (SRS) has been involved in a collision in which the center tunnel area has been damaged, inspect the mounting
and bracket for deformation. If damaged, a new RCM must be installed whether or not the air bags have deployed. In addition, make sure the
area of the RCM mounting is restored to its original condition.
CAUTION:
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Prior to removal of the module, it is necessary to upload module configuration information to the diagnostic tool. This information needs
to be downloaded into the new module once installed.
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When installing a new restraints control module (RCM), always make sure the correct RCM is being installed. The RCM 40-pin
connector is keyed differently for vehicles with side air curtains and side air bags than the 40-pin connector for vehicles without side air
curtains and side air bags. Do not force the 40-pin connector onto the RCM. If the connector is forced onto the RCM, damage to the
RCM and/or connector will occur.
NOTE: When installing a new restraints control module (RCM), always make sure the correct RCM is being installed. If an incorrect RCM is installed,
erroneous DTCs will result.
The RCM carries out the following functions:
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deploys the air bag(s) in the event of a deployable crash.
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activates the safety belt buckle pretensioner and safety belt adaptive load limiting retractor to control tension on the safety belt.
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monitors the SRS for faults.
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illuminates the air bag indicator if a fault is detected.
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communicates through the data link connector (DLC) the on-demand or continuous Diagnostic Trouble Codes (DTCs).
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signals the instrument cluster module to activate a chime if the air bag indicator is not available and another SRS fault exists.
The RCM monitors the SRS for possible faults. If a fault is detected while the ignition switch is in the ON position, the RCM will illuminate the air bag
indicator located in the instrument cluster.
When the ignition is cycled (turned OFF and then ON), the air bag indicator will prove out by lighting for 6 seconds and then off. If a SRS fault exists,
the air bag indicator will illuminate and remain illuminated for the rest of the key cycle. The RCM will also communicate the on-demand (current) and
continuous (historical) DTCs through the DLC, to the diagnostic tool. If the RCM requests illumination of the air bag indicator and the air bag indicator
does not function, the instrument cluster module will automatically activate an audible chime. The chime is a series of 5 sets of 5 tone bursts. If the chime
is heard, the SRS and the air bag indicator require repair.
The RCM includes a backup power supply. This feature provides sufficient backup power to deploy the air bags in the event that the ignition circuit is
lost or damaged during impact. The backup power supply will deplete its stored energy approximately one minute after the battery ground cable is
disconnected.
