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.
BCM Functions
The body control module (BCM) is capable of accomplishing multiple body control functions. Components directly connected to the BCM are controlled by the BCM outputs. The BCM can control its outputs based on input information it obtains from sensors and switches that are directly connected to the BCM, or by receiving information from other vehicle systems connected to the class 2 serial data link. The BCM evaluates this information and controls certain body systems by commanding an output on or off.
The BCM is also capable of commanding other vehicle systems to control functions that are not directly wired to and/or controlled by the BCM. The BCM accomplishes this task by sending specific messages on the class 2 serial data link. The vehicle system capable of performing such function will respond to the BCM message.
The BCM controls/monitors the following functions:
- Audible warnings
- Indicators control
- Interior lighting
- Exterior lighting
- Power/automatic door locks
- Keyless entry
- Content theft deterrent
- Personalization
- Serial Power Modes
- Electrical Power Management
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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.