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Diagnosis System

  1. CHECK DLC3 
    1. The ECU uses ISO 15765-4 for communication. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format.
      Fig 1: Identifying DLC3 Connector Terminals
      G05292261Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      DLC3 TERMINALS REFERENCE

      Terminal No. (Symbols) Terminal Description Condition Pulse condition
      7 (SIL) - 5 (SG) Bus "+" Line During transmission Pulse generation
      4 (CG) - Body ground Chassis Ground Always Below 1 Ω
      5 (SG) - Body ground Signal ground Always Below 1 Ω
      16 (BAT) - Body ground Battery positive Always 10 to 14 V
      6 (CANH)-14 (CANL) CAN bus line Ignition switch OFF(1) 54 to 69 Ω
      6 (CANH)-16 (BAT) HIGH-level CAN bus line Ignition switch OFF(1) 6 kΩ or higher
      6 (CANH) - 4 (CG) HIGH-level CAN bus line Ignition switch OFF(1) 200 Ω or higher
      14 (CANL)-16 (BAT) LOW-level CAN bus line Ignition switch OFF(1) 6 kΩ or higher
      14 (CANL)-4 (CG) LOW-level CAN bus line Ignition switch OFF(1) 200 Ω or higher
      NOTE:
      (1) Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the ignition switch, any other switches, or the doors.

      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 intelligent tester (with CAN VIM) to the DLC3, turn the ignition switch ON and attempt to use the tester. If the screen displays UNABLE TO CONNECT TO VEHICLE, a problem exists in the vehicle side or the tester side.

      Fig 2: Connecting Intelligent Tester To DLC3
      G05292262Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      • 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 is probably in the tester itself. Consult the Service Department listed in the tester's instruction manual.
  2. SYMPTOM SIMULATION 

    HINT:

    The most difficult case in troubleshooting is when no symptoms occur. In such cases, a thorough customer problem analysis must be carried out. Then the same or similar conditions and the environment in which the problem occurred in the customer's vehicle should be simulated. No matter how experienced or skilled a technician may be, if he proceeds to troubleshooting without confirming the problem symptoms, he will likely overlook something important and make a wrong guess at some points in the repair operation. This leads to a standstill in troubleshooting.

    1. Vibration method: When vibration seems to be the major cause.

      HINT:

      Perform the simulation method only during the primary check period (for approximately 6 seconds after the ignition switch is turned ON).

      1. Slightly vibrate the part of the sensor considered to be the problem cause with your fingers and check whether the malfunction occurs.

        HINT:

        Shaking the relays too strongly may result in open relays.

      2. Slightly shake the connector vertically and horizontally.
      3. Slightly shake the wire harness vertically and horizontally.

        The connector joint and fulcrum of the vibration are the major areas to be checked thoroughly.

        Fig 3: Checking Connectors And Sensors For Vibration
        G05292263Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. FUNCTION OF PASSENGER AIRBAG ON/OFF INDICATOR 
    1. Initial check:
      1. Turn the ignition switch ON.
      2. The passenger airbag ON/OFF indicator ("ON" and "OFF") comes on for approximately 4 seconds, then goes off for approximately 2 seconds.
      3. Approximately 6 seconds after the ignition switch is turned ON, the passenger airbag ON/ OFF indicator will show ON or OFF depending on the conditions listed below.
        INDICATOR CONDITION CHART

        Condition ON Indicator OFF Indicator
        Vacant OFF OFF
        Adult is seated ON OFF
        Child Is seated OFF ON
        Child restraint system is set OFF ON
        Occupant classification system failure OFF ON

        HINT:

        • The passenger airbag ON/OFF indicator is based on the timing chart below in order to check the indicator light circuit.
        • When the occupant classification system has trouble, both the SRS warning light and the passenger airbag ON/OFF indicator ("OFF") come on. In this case, check the DTCs in "AIRBAG SYSTEM" first.
          Fig 4: Identifying Passenger Airbag ON/OFF Indicator Condition
          G05292264Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  4. CHECK PASSENGER AIRBAG ON/OFF INDICATOR 
    1. Turn the ignition switch ON.
    2. Check that the passenger airbag ON/OFF indicator ("ON" and "OFF") comes on for approximately 4 seconds, then goes off for approximately 2 seconds.

      HINT:

      Refer to the table in the previous step regarding the passenger airbag ON/OFF indicator when the ignition switch is turned ON and approximately 6 seconds pass.

      Fig 5: Identifying Passenger Airbag ON/OFF Indicator
      G05292265Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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