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.
Description & Operation: Notes
The multiplex control system uses a Body Control Module (BCM) and 11 Local Control Units (LCU's) to manage the following electrical systems in the vehicle: power window control, power door lock control, automatic drive positioner control, power seat control, time control system, anti-theft system, step light control, illumination control, door mirror automatic tilt down reverse control and multi-remote control. See Fig 1 . Some electrical systems are directly connected to the BCM, while some electrical loads and switches are connected to the appropriate LCU.
The BCM uses 2 data lines, connected between BCM and LCU's, to establish communication and control with each LCU. System has a sleep/wake-up control mode to turn on/shut off the communication between BCM and LCU's, as necessary, to prevent unnecessary power consumption. If computing function of the BCM is malfunctioning, system will set LCU's in fail-safe control mode.
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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.