Corvette V8-5.7L VIN G (1997)
Body Control Module: Component Tests and General Diagnostics
BCM Functions
The Body Control Module (BCM) is capable of performing multiple body control functions. The BCM outputs control the systems that are directly
connected to the BCM. The BCM controls the outputs using this input information received from the sensors and the switches directly connected to the
BCM. The BCM also borrows information from other systems on the serial data line in order to control the outputs. The BCM evaluates this information
and commands an Output ON or OFF in order to control certain body systems. The BCM also commands other systems to control systems that are not
directly wired to the BCM. The BCM accomplishes this by sending specific messages on the serial data line. The system capable of performing this
function will respond to the message.
The BCM is capable of performing the following functions:
^
Bulb over voltage protection
^
Door ajar status
^
Exterior light control
-
Approach lighting
-
Backup lights
-
Daytime Running Lights (DRL)
-
Headlights flash-to-pass feature
-
Front fog lights
-
Front turn signal monitoring
-
Rear fog lamps (export only)
^
Hatch ajar status
^
Hatch release control
^
Heated mirror control
^
Hood ajar status
^
Horn relay
^
Interior light control
-
Center console lights
-
Courtesy lights
-
HVAC illumination
-
Illuminated entry feature
-
Lower courtesy lights
-
PRNDL display
^
Key-in-ignition status
^
Load shed control
^
Monitored loads control
^
Pass-Key(R) (Personalized Automotive Security System)
^
Power mode master
^
Rear defogger control
^
Steering column lock/unlock control
^
TCS activation control
^
Universal Theft Deterrent (UTD)
^
Vehicle configuration (RPO codes)
BCM Wake-Up/Sleep States
The Body Control Module (BCM) is able to control or perform all of the BCM functions in the wake-up state. The BCM enters the sleep state when
active control or monitoring of system functions has stopped, and the BCM has become idle again. The BCM must detect certain wake-up inputs before
entering the wake-up state. The BCM monitors for these inputs during the sleep state, where the BCM is able to detect switch transitions that cause the
two wake-up states, activated or deactivated. Multiple switch wake-ups are need in order to sense both the insertion and the removal of the ignition key.
This would allow the BCM to enter a sleep state when the key is in the ignition.
The BCM will enter a wake-up state if any of the following wake-up inputs are detected:
^
Any activity on the serial data line
^
Hatch ajar switch
^
Hatch release switch
^
Door ajar switch
^
Key-in-ignition switch
^
Monitored load relay
^
Park/fog/headlights are on
^
The BCM experiences a battery disconnect and reconnect condition.
^
The ignition is turned ON.
The BCM will enter a sleep state when all of the following conditions exist:
^
No activity exists on the serial data line.
