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.
Multiplex Communication System: Notes
Multiplex communication system includes the following systems:
- Automatic Air Conditioning.
- Automatic Light Control.
- Back Door Opener/Luggage Compartment Door.
- Charging.
- Combination Meter.
- Cruise Control.
- Door Lock Control and Wireless Door Lock Control.
- Electronically Controlled Transmission and A/T Indicator.
- Engine Control.
- Front Window Deicer.
- Headlight.
- Interior Light.
- Key Reminder and Seat Belt Warning.
- Light Auto Turn Off.
- Power Window.
- Rear Window Defogger and Mirror Heater.
- Theft Deterrent.
The system is comprised of the communication modes of the body ECU, engine control module, anti-theft ECU, power window master SW, combination meter and A/C control assembly. The body electrical systems are controlled by a serial communication in which each ECU is linked to another via a single communication line. This system is also equipped with a self-diagnosis function. The table below shows the systems under the control of the MPX and related ECUs (communication modes). See Fig 1.
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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.