General Description
The body control module (BCM) utilises the information from various sensors and switches to control the many electrical body functions on the vehicle. The BCM also interacts with other on-board control modules that are not contained within the BCM environment. The engine control module (ECM), transmission control module (TCM), anti-lock braking system (ABS) and all-wheel drive (AWD) systems are all utilised by the BCM to exchange information via the CAN bus. The BCM also controls the body control module-export (XBCM) which is used in conjunction with the BCM for the purpose of arming and disarming the anti-theft alarm system.
The body control module (BCM) on the MY 2007 Antara is located behind the heating, ventilation and air conditioning (HVAC) panel in the centre console, and is connected to the vehicle's wiring harness via 7 connectors. Each connector has a unique colour and connector coding to prevent a faulty connection.
System Functions
The BCM has two modes of operation; awake and sleep modes. In the awake mode the BCM is able to perform all of its required functions. The sleep mode or low power mode is entered when the normal monitoring of system functions and active control of the vehicle has stopped, and a time limit has passed. i.e., when the ignition is turned off, key removed from the ignition and the doors are closed. The BCM will enter the awake mode again as soon as certain wake-up inputs are detected, such as remote control operation, door opening and lighting functions.
The input and output signals from the BCM are transmitted via normal wiring and the CAN bus. The high-speed CAN bus (HSCAN) and low-speed CAN bus (LSCAN) are not physically connected to each other, so the BCM uses an internal 'gateway' function to enable communication between the two. This function allows the BCM to communicate with other modules, for example; information on the vehicle speed will be received by the ABS on HSCAN, and has to be interpreted by the instrument panel cluster (IPC) on LSCAN. This information on HSCAN is translated by the BCM into the low speed language for LSCAN and relayed to the IPC.
One of the most important responsibilities of the BCM is the power mode master (PMM) function. The PMM is the information used by the various on-board control modules on the vehicle to determine its operation. The PMM uses the ignition switch position information received by the BCM to determine which power mode (off, accessory, run, crank) is required, and communicate this information to the relevant on-board modules via the CAN bus. Each power mode will activate the relevant control modules concerned with the individual request, i.e., with the ignition switch in the crank position, the control modules which have no function necessary to start the engine will be off, so as to provide the maximum power for the starting operation.
IPC - Audible Warnings
The IPC warnings are activated by the BCM, via information from the various on-board control modules, sensors and switches. The warning indicators are complemented by the chime module located inside the IPC, which is used to generate audible warning signals and alert the driver of a system concern or critical vehicle condition. The IPC receives the chime control messages from the BCM via LSCAN and generates a range of audible signals.
The range of warning sounds are listed in order of priority the table below.
| Event | |
|---|---|
| 1. | Seat belt reminder - driver |
| 2. | Key-in-ignition reminder |
| 3. | Headlamps on reminder |
| 4. | Hazard warning lamps on/off |
| 5. | Turn signal lamps on/off |
Retained Accessory Power
The vehicle incorporates a retained accessory power (RAP) device, and is utilised by the BCM as a power and labour saving system. The RAP system effectively allows certain devices in the vehicle to be operational for a period of 10 minutes after the ignition is shut off and the doors are closed. To determine whether the RAP mode should be initiated, the BCM monitors battery power to detect any decreases in capacity below a certain limit, and checks the ignition switch position and door status. If the ignition is off and the key removed, providing no door is open, the RAP system is initiated and will run for approximately 10 minutes. The system is automatically deactivated as soon as the doors are open.
Some of the devices that are powered in RAP mode are listed below.
- Electric sunroof
- Electric windows
- Switches
- Audio system
- Cigarette lighter