Body Control Module: Notes

The body control module (BCM) supplies vehicle occupants with visual and audible information and controls various vehicle functions. To provide and receive information, the module is interfaced to the vehicle's serial bus communications network (PCI). This network consists of the powertrain control module (PCM), the mechanical instrument cluster (MIC), BCM, the airbag control module (ACM), the controller antilock brake (CAB), the HVAC control module and the radio. The RKE and Tire Pressure Monitor modules have serial links to the BCM. The BCM is operational when battery power is supplied to module and not in Battery Save Mode. The BCM provides the following features:

Vehicle Entry
Virtual lock
Automatic Door Lock
Exterior lighting
Interior Lighting (Courtesy/Reading Lamps)
Tire pressure monitor input
Horn
Power Windows. Vehicle Theft
Battery Save Feature
Door Lock Inhibit
Battery Protection
The BCM will automatically turn off all exterior lamps after 3 minutes and all interior lamps after 15 minutes after the ignition is turned off, if they are not turned off by the driver.
Chime Driver
BCM Diagnostic Reporting
Headlamp Time Delay
Illuminated Entry
Fade to Off
This feature dims the interior lighting (courtesy lamps) gradually if the BCM does not receive any new inputs that would cause the interior lamps to remain on.
PWM Instrument Panel Dimming (HVAC and radio)
Bus Message Panel Dimming to Cluster, HVAC & Radio
Door Lock Inhibit
This feature disables the door lock functions if the key is in the ignition and either front door is ajar. Pressing the RKE lock/unlock button under these conditions, result in normal lock/unlock activation.

NOTE: Do not swap the body control module between vehicles or body control modules off the shelf.

Engineering does not recommend that service, dealers or the plant swap Body Control Modules (BCM) between vehicles or off the shelf. The BCM has internal diagnostic capability that assists in diagnosing the system. When an "Open" or a "Short" circuit exists, the DRBIII® can be used to read the BCM codes. The codes are very descriptive in identifying the appropriate feature that has faulted.