LW100 L4-2.2L VIN F (2002)
Body Control Module: Description and Operation
Body Control Module Functions
A/C Request
STANDARD HVAC
A/C request is made by the HVAC control head supplying voltage to circuit 66 to the BCM. The BCM will then request the serial data link to the
engine controller to operate the compressor. The BCM provides evaporator freeze protection by monitoring engine speed and ambient temperature.
AUTOMATIC CLIMATE CONTROL
The ACC system will request air compressor over serial data from the ACC module to the BCM. The BCM will send the request on to the PCM or
ECM, if request is valid.
Anti-Lockout
The anti-lockout feature aids in preventing the customer from locking their car keys in the vehicle. This is a programmable feature using the Tech 2. The
options are enable and disabling the feature. The feature works as follows: If the keys are in the ignition, and a manual door lock switch is activated with
any door open, the BCM will lock all doors, then within 500 mS. the drivers door will unlock. This feature can be overridden in two ways:
^
The doors will lock if a lock command from a Remote Keyless Entry (RKE) transmitter is sent to the BCM
^
Manually push the lock tab on the door
Audible Warnings
The Body Control Module (BCM) will provide and audible warning for various events relating to the vehicle. The functions that provide and Audible
Warning are Key in Ignition, Lights On, Occupant Restraint (seat belt) and Park Brake.
Key in Ignition Audible Chime
The BCM will provide an audible chime if the key is left in the ignition in either off or Accessory position with the drivers door open. The chime rate
for this chime is 150 chimes per minute. The key in ignition chime has a higher priority than the lights on chime.
Lights On Audible Chime
The BCM will provide an audible chime if the park lights are on and the drivers door open. In addition one of two other conditions exists. The key is
out of the ignition or the key is in the ignition at the off position and has not been turned. The BCM will chime at a rate of 200 chimes per minute
until the conditions are removed.
Occupant Restraint Audible Chime
The BCM will provide an audible chime based on the class II message received from the SDM if the drivers seat belt is not buckled when the ignition
is turned to run or crank. The chime rate for this feature is 50 chimes per minute.
Park Brake Audible Chime
The BCM will provide an audible chime for park brake when the park brake is applied and the vehicle speed is higher than 3 mph. The chime rate for
this feature is 200 chimes per minute.
Automatic Climate Control (ACC)
The automatic climate control system controls the heating, cooling and ventilation in the vehicle. The system is made up of, HVAC control module,
Passenger Compartment Temperature Sensor, Outside Temperature Sensor, Solar Load Sensor and Body Control Module. The HVAC control module
uses the information from sensors to adjust temperature in the vehicle to suit the desired settings.
Automatic Lighting Control (ALC)
The Body Control Module (BCM) monitors circuit 79 to determine if the headlamps (park lamp) switch is active or inactive. The Automatic Lighting
Control (ALC) system will be inactive if the headlamp, parklamp switch is active. The headlamp relay is commanded on by the BCM through circuit
352. The BCM also monitors 352 for feedback when the headlamp relay is commanded. The system uses light sensor circuit 1137 to switch the ALC on
after dark.