Body Control Systems: Description and Operation

Module Controlled Functions

NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

Multifunction Electronic Modules

There are 2 multifunction electronic modules on this vehicle. They include the:

- Body Control Module B (BCM-B)
- SJB

Body Control Module B (BCM-B)

The BCM-B controls multiple vehicle systems which include:

- Ambient lighting
- Convertible top (if equipped)
- Convertible top drop window function (if equipped)
- Intrusion/inclination sensor
- Luggage compartment lid release inhibit (convertible)
- Reverse lamps
- Stoplamps
- Turn signals (rear only)

The BCM-B is located in the right side of the luggage compartment and is behind the audio subwoofer amplifier, which are both bolted to the BCM-B bracket.

Smart Junction Box (SJB)

NOTE: The time out for the battery saver relay and the accessory delay relay (both are controlled by the SJB) is 1 minute if the vehicle has less than 80 km (50 miles). Once the vehicle passes the approximate mileage threshold of 80 km (50 miles), the time out for both relays is 10 minutes, as described by the Owner's Literature. For the battery saver relay, refer to Lighting and Horns. For the accessory delay relay, refer to Windows and Glass.

The SJB is a combination of a multifunction electronic module and an interior fuse panel. The SJB functions control multiple vehicle systems which include:

- Battery saver
- Exterior lighting
- Heated rear window
- Interior lighting
- Perimeter anti-theft (if equipped)
- Power locks
- Remote Keyless Entry (RKE)
- Tire Pressure Monitoring System (TPMS)
- Interfacing with the Instrument Panel Cluster (IPC) for the TPMS warning lamp and other warning chimes

The SJB is located behind the RH A-pillar lower trim panel.

Post Crash Alert

The post crash alert function is controlled by the SJB. If the Restraints Control Module (RCM) determines an impact of severity enough to deploy air bags has occurred (the air bags may or may not be deployed by the RCM), the RCM will send a message to the Instrument Panel Cluster (IPC) over the High Speed Controller Area Network (HS-CAN) that an air bag deployable impact has occurred.

The IPC sends the message to the SJB over the Medium Speed Controller Area Network (MS-CAN). The SJB activates the post crash alert function by repeatedly cycling the horn on 3 times, then off for 4 seconds, until the battery dies or the function is turned off. The hazard lights will also flash with the horn sounding, but will keep flashing during the horn off cycle.

The post crash alert function can be turned off by:

- pressing the hazard switch (which may need to be pressed more than once).
- pressing the RKE transmitter UNLOCK button.
- pressing the RKE transmitter PANIC button.

The post crash alert feature acts similar to the perimeter alarm, but the horn cycle rate is different. The perimeter alarm function cycles the horn on and off, in regular intervals until 2 minutes and 45 seconds have elapsed, the battery dies or the function is turned off. Turning the ignition to the ON position will not deactivate the post crash alert, but will deactivate an activated perimeter alarm.

The post crash alert function cannot be configured off.

For the perimeter anti-theft, refer to Antitheft and Alarm Systems.

For the battery saver, heated rear window, and power windows, refer to Windows and Glass.

For the convertible top, refer to Convertible Top.

For the exterior lighting, refer to Lighting and Horns.

For the interior lamps and illuminated entry, refer to Lighting and Horns.

For the power door locks, and the RKE system, refer to Doors, Hood and Trunk &/or Locks.

For the TPMS, refer to Wheels and Tires.

For the warning chimes, refer to Instrument Panel, Gauges and Warning Indicators.