Body Control Module: Description and Operation
Body Control Module (BC1)
The BC1, similar in operation to the BMW General Module, controls several systems on the MINI. It is connected to the K-Bus to allow sub-systems to communicate with other systems and to enable diagnostic communication with the sub-systems. The BC1 is located at the base of the A Pillar on the right hand side of the vehicle. It utilizes four (4) connections: one 20-pin connection and three (3) 54-pin connections.
BC1 mounted at lower A Pillar right hand side of vehicle.
Systems Controlled by the BC1 are:
- Electrical Load Management
- Vehicle Information System
- Central Locking/Remote Locking
- Power Windows
- Anti-Theft System (DWA)
- Exterior/Interior Lighting
- Front and Rear Wipe/Wash
- Heated Rear Window/Heated Front Windshield
- Fresh/Re-Circulation Air Control
- Air Conditioning
Electrical Load Management
Purpose of the System
The purpose of the Electrical Load Management System is to reduce battery drain while vehicles are transported, stored or not used for long periods of time. Two modes of operation are possible:
- Transit Mode
- Normal Mode
Transit Mode
Transit Mode is used to prevent excessive battery drain during movement of the vehicle from the manufacturing point to the dealer. After vehicle manufacture, the BC1 is programmed with correct market and equipment information and placed in transit mode. Transit mode allows some limited electrical functionality.
The electrical load management system is changed at the VPC or dealer to normal mode using the DISplus.
Normal Mode
In Normal Mode the electrical management system provides three different methods of protection for the vehicle electrical system.
- Low Voltage
- Sleep Mode
- Power Down During Cranking
Low Voltage
In the event of the battery voltage falling below 11.8 volts the BC1 will deactivate and inhibit the operation of the heated rear window and optional heated front screen until the voltage level exceeds 12.2 volts.
Sleep Mode
To reduce closed circuit current draw the BC1 enters its sleep mode 16 minutes after switching off terminal R or within two minutes of externally locking the car. The BC1 will wake up if the ignition is switched from position 0 to position 1 or the BC1 senses a change at one of its monitored inputs.
The K-Bus will enter a pre-sleep mode if no bus messages are received within 50 seconds and sleep mode if no messages are received in 60 seconds. The BC1 or any module on the K-Bus can initiate a wake-up call.
Power Down During Cranking
During starting of the engine certain loads are deactivated to allow maximum voltage to be applied to the starter motor. These loads are then re-introduced over a 2 second period after the engine has started in order to limit the current draw from the battery and load on the alternator.
The power down is limited to a maximum of 45 seconds, after which time all loads are enabled. This ensures that functions are not inhibited in the event of an ignition switch malfunction or incorrect cranking signal received by the BC1.
Vehicle Information Storage
The BC1 stores the total mileage and service interval data (SIA) in memory as back up for the IKE; this function is identical to that of the light switch center (LSZ) on the E46. The Vehicle Identification Number (VIM) is entered during coding of the BC1 and can only be over-written if the total mileage is less than 100 km. The VIN is stored in the IKE and BC1 are checked each time the ignition is switched on. The mileage and SIA data is also updated in the BC1 after 100 km of continuous driving. The BC1 will not accept mileage from the IKE if the value stored is over 1000 km less than that stored in the IKE. If this occurs the BC1 must be replaced.