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Diagnosis System

  1. DESCRIPTION 
    1. The door ECUs control the power window control system functions on the vehicle. Power window control system data and the Diagnostic Trouble Code (DTC) can be read in the Data Link Connector 3 (DLC3) of the vehicle. When the system seems to be malfunctioning, use the hand-held tester to check for malfunctions and perform repairs.
  2. CHECK DLC3 

    HINT:

    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: Checking DLC3
    G02956608Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    DLC3

    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 ohms
    SG (5) - Body ground Signal ground Always Below 1 ohms
    BAT (16) - Body ground Battery positive Always 10 to 14 V

    If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector.

    HINT:

    Connect the cable of the hand-held 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 with the tester.

    • If communication is normal when the tester is connected to another vehicle, inspect the DLC3 of the original vehicle.
    • If communication is still not possible when the tester is connected to another vehicle, the problem may be in the tester itself. Consult the Service Department listed in the tester's instruction manual.
    Fig 2: Connecting Cable Of Hand-Held Tester To DLC3
    G02956609Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. INSPECT BATTERY VOLTAGE 

    Standard: 11 to 14 V 

    If the voltage is below 11 V, recharge or replace the battery before proceeding.