Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Body Control Module
2009 Chevrolet Uplander LT, 3.9 MSECTION Body Control Module
The various body control module (BCM) input and output circuits are described in the corresponding functional areas indicated on the BCM electrical schematics. The BCM functions include the following:
- Battery rundown protection-Inadvertent power-Refer to Interior Lighting Systems Description and Operation .
- BTSI/automatic transmission shift lock control-Refer to Automatic Transmission Shift Lock Control Description and Operation .
- Bulb check-Refer to Instrument Cluster Description and Operation .
- Chimes-Refer to Audible Warnings Description and Operation
.
- Check gages
- Content theft deterrent
- Door ajar warning
- Headlamps ON
- Key-in-ignition
- Oil reset
- Park brake warning
- Seat belt not fastened
- Turn signal ON
- Vehicle theft deterrent
- Door lock interface-Refer to Power Door Locks Description and Operation .
- Exterior and interior lighting control-Refer to Exterior Lighting Systems Description and Operation
.
- Automatic lighting control
- Backup lamps
- Daytime running lights (DRL)
- Fog lamps
- High/low beam headlamps
- Park brake lights
- Turn hazard lamps
- Gage control-Refer to Instrument Cluster Description and Operation .
- Heated seats-Refer to Heated/Cooled Seat Schematics .
- Horn interface-Refer to Horn Schematics .
- Instrument cluster indicator control-Refer to Instrument Cluster Description and Operation .
- Interior lighting-Refer to Interior Lighting Systems Description and Operation .
- Key-in-ignition sensing-Refer to Audible Warnings Description and Operation .
- Parking brake state sensing-Refer to Brake Warning System Description and Operation .
- Retained accessory power (RAP)-Refer to Retained Accessory Power (RAP) Description and Operation .
- Rear compartment interface-Refer to Power Door Locks Description and Operation .
- Rear defogger-Refer to Rear Window Defogger Description and Operation .
- Remote function control-Refer to Keyless Entry System Description and Operation .
- RFA communication link-Refer to Keyless Entry System Description and Operation .
- Seat belt use sensing-Refer to Seat Belt System Description and Operation .
- Theft deterrent vehicle/content-Refer to Content Theft Deterrent (CTD) Description and Operation .
- Theft deterrent vehicle/content-Refer to Immobilizer Description and Operation .
- Washer solvent level sensing-Refer to Wiper/Washer System Description and Operation .
- Wiper/washer-Refer to Wiper/Washer System Description and Operation .
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.