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Diagnosis System

  1. DESCRIPTION 

    The ECU controls the cruise control system of the vehicle. The data and DTCs relating to the cruise control system can be read from the DLC3 of the vehicle. If either DTC is not displayed when checking for DTCs, there may be a problem with the combination meter or the CAN communication and multiplex communication system. Use the intelligent tester to check and solve the problem.

  2. CHECK DLC3 
    1. The vehicle's ECM uses ISO 9141-2 for communication. The terminal arrangement of DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.
      Fig 1: Identifying DLC3 Terminals
      G04091949Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      DLC3 TERMINALS DESCRIPTION AND SPECIFIED CONDITION TABLE

      Terminal No. Terminal Description Condition Specified Condition
      4 Chassis ground Always Below 1 Ω
      7 Bus "+" line During transmission Pulse generation
      16 Battery positive Always 11 to 14 V

      HINT:

      If the display shows "UNABLE TO CONNECT TO VEHICLE" after connection the intelligent tester to the DLC3 and turning the ignition ON, there is a problem either with the vehicle or with the tool.

      • If communication is normal when connection the tool to another vehicle, inspect the DLC3 on the original vehicle.
      • If communication is still not possible when connection the tool to another vehicle, the problem is probably in the tool itself. Consult the Service Department listed in the tool's instruction manual.
  3. CHECK INDICATOR 
    1. Turn the ignition switch on.
      Fig 2: Checking Cruise Control Indicator
      G04091950Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check that the CRUISE main indicator light illuminates when the cruise control main switch is turned ON, and that the indicator light turns off when the main switch is turned OFF. If the results are not as specified, inspect the CRUISE main indicator light circuit (See CRUISE MAIN INDICATOR LIGHT ).
      Fig 3: Identifying Cruise Main Indicator Light Blinking Pattern
      G04091951Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      • While driving with cruise control, the ECM activates AUTO CANCEL of the cruise control system when a malfunction in one of the following occurs: vehicle speed sensors, stop light switch or other related parts. When AUTO CANCEL is activated, the CRUISE main indicator light outputs the blinking pattern shown to the left. At the same time, data of the malfunction is stored as a DTC.