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Diagnosis System

  1. DESCRIPTION 

    The network gateway ECU controls the functions of the Multiplex Communication System (MPX) of the vehicle. Data of the MPX and the Diagnostic Trouble Codes (DTCs) can be read in the Data Link Connector 3 (DLC3) of the vehicle.

  2. CHECK DLC3 

    The vehicle uses ISO 9141-2 communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.

    Fig 1: Identifying DLC3 Connectors Terminal
    G05294421Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    VOLTAGE AND RESISTANCE SPECIFICATION

    Symbols (Terminal No.) Terminal Description Condition Specified Condition
    SIL (7) - SG (5) Bus "+" line During transmission Pulse generation
    CG (4) - Body ground Chassis ground Always Below 1 Ω
    SG (5) - Body ground Signal ground Always Below 1 Ω
    BAT (16) - Body ground Battery positive Always 11 to 14 V

    HINT:

    Connect the cable of the intelligent tester to the DLC3, turn the ignition switch ON and attempt to use the tester. If the screen displays the message UNABLE TO CONNECT TO VEHICLE, there is a problem either with the vehicle or the tester.

    If communication is normal when the tester (with CAN VIM) is connected to another vehicle, inspect the DLC3 on the original vehicle.

    If communication is still impossible when the tester is connected to another vehicle, the problem is probably in the tester itself.

    Fig 2: Connecting Intelligent Tester To DLC3
    G05294422Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002