Holden - Body Control Module
The Body Control Module, or BCM, is responsible for most of the car's ancillary functions unrelated to the power-train. These include; illumination, central locking, remote lock/unlock, power windows and more.
VT/VX/VY/VZ Commodores
The BCM for these Commodores is located above the foot-well on the driver's side of the vehicle. There are four BCM types for these vehicles, depending on the body type and badge. These are; Low, Mid, High, and Lux. Low level BCM modules are used for vehicles without power windows. Mid level BCM modules are fitted to vehicles with power windows (such as the Executive, Acclaim, S and SS models). Lux BCM modules are fitted to Berlina and select Calais models while High level BCM modules are fitted to Calais models and Statesmans. The table below lists the features available on each BCM level.
| BCM Function | LOW | MID | LUX | HIGH |
|---|---|---|---|---|
| Central Door Locking | Y | Y | Y | Y |
| Boot Release | Y | Y | Y | Y |
| Electric Windows | N | Y | Y | Y |
| Electric Radio Antenna | N | N | Y | Y |
| Internal Dome Light | Y | Y | Y | Y |
| Rear Light Failure Warning Light | N | N | N | Y |
| Wiper Speed Variable Action | N | N | Y | Y |
| Wiper Fixed Dwell Action | Y | Y | N | N |
| Wagon Rear Wiper Control | N | Y | Y | N |
| Speed Sensitive Power Steering | N | N | N | A |
| Instrument Light Dimming | N | N | Y | Y |
| Automatic Lights Off | Y | Y | Y | Y |
| Twilight Lights On | N | N | N | Y |
| Anti-Theft | N | N | Y | Y |
| Engine Disable | Y | Y | Y | Y |
| Radiator Low-Speed Fan | Y | Y | Y | Y |
| Priority Key System | N | N | N | Y |
| Cruise Control Interface | Y | Y | Y | Y |
| SRS Shutdown | Y | Y | Y | Y |
| Serial Data Interface | Y | Y | Y | Y |
| Heated Rear Window Control | Y | Y | N | N |
| Air Conditioning Interface | Y | Y | N | N |
ALDL
The VT/VX/VY/VZ Commodores have a primary serial bus, and an optional auxiliary serial bus. The BCM is the bus master of the primary serial bus. Vehicles equipped with a High or Lux level BCM feature an auxiliary serial bus for the purpose of isolating ancillary modules such as the climate control module and the radio from the power-train. Vehicles without an auxiliary serial bus place the radio on the primary bus with the PCM, ABS and SRS modules. The primary serial bus can usually be identified as a red wire with a black stripe whilst the auxiliary serial bus can usually be identified as a green wire with a white stripe. The BCMs on VT/VX/VY/VZ Commodores can be controlled via ALDL using Mode 4 commands. The BCM on these models is addressed on the ALDL bus using message ID F1. The table below lists just some of the commands that can be issued to a BCM over ALDL.[1]
| ID | Mode | Bytes | Function |
|---|---|---|---|
F1 |
04 |
66 04 00 00 01 00 00 00 00 00 01 00 00 00 00 00 00 00 |
Turn Interior Light On |
F1 |
04 |
66 04 00 01 00 00 00 00 00 01 00 00 00 00 00 00 00 00 |
Turn Indicators On (Not Flashing) |
F1 |
04 |
66 04 00 00 40 00 00 00 00 00 40 00 00 00 00 00 00 00 |
Turn A/C LED On |
F1 |
04 |
66 04 00 00 04 00 00 00 00 00 04 00 00 00 00 00 00 00 |
Turn Low Speed Fan On |
F1 |
04 |
66 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 02 |
Central Locking Lock |
F1 |
04 |
66 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 03 |
Central Locking Deadlock |
F1 |
04 |
66 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 |
Central Locking Unlock Driver |
F1 |
04 |
66 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 01 |
Central Locking Unlock All |
F1 |
04 |
66 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 02 04 |
Pop Boot Lock |
F1 |
04 |
66 04 00 00 80 00 00 00 00 00 80 00 00 00 00 00 00 00 |
Operate Front Wipers |
F1 |
04 |
66 04 00 08 00 00 00 00 00 08 00 00 00 00 00 00 00 00 |
Drivers Window Down |
F1 |
04 |
66 04 00 04 00 00 00 00 00 04 00 00 00 00 00 00 00 00 |
Passenger Window Down |
F1 |
04 |
66 04 00 40 00 00 00 00 00 40 00 00 00 00 00 00 00 00 |
Power Window Relay |
F1 |
04 |
66 04 00 00 10 00 00 00 00 00 10 00 00 00 00 00 00 00 |
Horn |
F1 |
04 |
66 04 00 02 00 00 00 00 00 02 00 00 00 00 00 00 00 00 |
Illumination Relay |