System Description
- MPX (MULTIPLEX COMMUNICATION NETWORK)
The MPX connects the ECUs of this vehicle and uses an ON-OFF signal (binary 0 and 1) to communicate with each ECU. The ECU operates the actuator based on the other ECU information. For example, the ECM (PCM) allows the engine to start based on the transponder key ECU information. The MPX consists of 3 networks: AVC-LAN (Audio Visual Communication Local Area Network), BEAN (Body Electronics Area Network) and CAN (Controller Area Network). The gateway ECU is connected to and coordinates communication between the 3 networks.
MPX Cross-reference
MPX CROSS-REFERENCENetwork Protocol Wire Harness Speed Data length AVC-LAN TOYOTA original Twisted twin wire Maximum 17,800 bps* 0 to 32 byte BEAN TOYOTA original Single line Maximum 10,000 bps* 1 to 11 byte CAN ISO 15765-4 Twisted twin wire 500,000 bps* (Maximum 1 Mbps) 1 to 8 byte HINT:
*: "bps" indicates bits per second.
- AVC-LAN (AUDIO VISUAL COMMUNICATION LOCAL AREA NETWORK)
The audio/visual system uses the AVC-LAN. The master ECU is connected to gateway ECU and sends the signal to the other ECUs. The wire harness is a twisted twin wire covered with the insulation. One wire is used for the positive voltage and the other wire is used for the negative voltage.
- BEAN (BODY ELECTRONICS AREA NETWORK)
The body electrical system uses the BEAN. The ECUs are connected to the gateway ECU like a daisy chain. This maintains the communication if the wire harness has an open circuit. The wire harness is a signal core line covered with insulation.
- CAN (COMMUNICATION AREA NETWORK)
The powertrain and chassis system use the CAN. The CAN circuit has 2 master ECUs. One master ECU is connected to the other master ECU by the main wire. The gateway ECU and other ECUs are connected to the main wire by the branch wire through the junction connector(s). The wire harness is a twisted twin wire covered with insulation. One wire (CANL) is 1.5 to 2.5 volts and the other wire (CANH) is 2.5 to 3.5 volts.