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Diagnosis System

  1. DESCRIPTION 
    1. Data of the system can be read in the Data Link Connector 3 (DLC3) of the vehicle. Therefore, when the system seems to be malfunctioning, use the intelligent tester to check for a malfunction and repair it.
  2. CHECK DLC3 
    1. The vehicle's ECM 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 Connector Terminal
      G04021879Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard 

      DLC3

      Tester Connection Condition Specified Condition
      7 (Bus + line) - 5 (Signal ground) During communication Pulse generation
      4 (Chassis ground) - Body ground Constant Below 1 Ω
      5 (Signal ground) - Body ground Constant Below 1 Ω
      16 (B+) - Body ground Constant 9 to 14 V

      HINT:

      If the screen displays a communication error message after you have connected the cable of the intelligent tester to the DLC3, turned the ignition switch ON and used the intelligent tester, the problem may be on the vehicle side or tester side.

      • If communication is normal when the tester is connected to another vehicle, inspect the DLC3 of the original vehicle.
      • If communication is still impossible when the tester is connected to another vehicle, the problem is probably in the tester itself, so consult the Service Department listed in the tester's instruction manual.
  3. INSPECT BATTERY VOLTAGE 
    1. Check the battery voltage.

      Standard voltage: 11 to 14 V 

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

  4. CHECK DIAGNOSIS 
    1. Turn the ignition switch ON.
    2. Operate the driver side switch of the master switch.
    3. Check the blinking pattern of the AUTO light as shown in the illustration.
      Fig 2: Identifying Master Switch
      G04116021Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 3: Blinking Pattern Of Light
      G04116022Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. If pattern (A) is displayed, reset power window regulator motor.
      2. If pattern (B) or (C) is displayed, check the wire harness.
      3. If the normal pattern is displayed, replace the multiplex network master switch.