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Diagnosis System

  1. DESCRIPTION 
    1. The HV control ECU has a self-diagnosis system. If the computer, hybrid vehicle control system or the components are not working properly, the ECU carries out a diagnosis to detect the malfunctions, and illuminates the master warning light in the combination meter together with indicators on the multi display, the HV system warning, the HV battery warning or the discharge warning.

      HINT:

      The master warning light illuminates when THS II fails and it blinks when in inspection mode.

      Fig 1: Identifying Master Warning Light
      G04473315Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 2: Identifying HV Battery Warning
      G04473316Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      • When troubleshooting OBD II vehicles, the only difference from the usual troubleshooting procedure is that you need to connect the OBD II scan tool complying with ISO 15031-4 or the intelligent tester to the vehicle, and read various data output from the vehicle's ECUs
      • OBD II regulations require that the vehicle's onboard computer illuminates the Malfunction Indicator Lamp (MIL) in the instrument panel when the computer detects a malfunction in: 1) the emission control systems/components, or 2) the powertrain control components (which affect vehicle emissions), or 3) the computers. In addition, the applicable Diagnostic Trouble Codes (DTCs) prescribed by ISO 15031-4 are recorded in the HV control ECU memory (see DIAGNOSTIC TROUBLE CODE CHART  ).

        If the malfunction does not recur in 3 consecutive trips, the MIL will go off automatically. However, the DTCs remain recorded in the HV control ECU memory.

        Fig 3: Identifying Malfunction Indicator Lamp
        G04473317Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      • To check the DTCs, connect the intelligent tester to the Data Link Connector 3 (DLC3) with the CAN vehicle interface module (CAN VIM). The intelligent tester enables you to erase the DTCs and check the freeze frame data and various forms of THS II data (for operating instructions, refer to their respective instruction manuals). The DTCs include SAE controlled codes and manufacturer controlled codes. SAE controlled codes must be set as prescribed by the SAE, while manufacturer controlled codes can be set by a manufacturer within the prescribed limits (see DIAGNOSTIC TROUBLE CODE CHART  ).
      • Freeze frame data:

        The freeze frame data records the driving condition when malfunction is detected. When troubleshooting, it can help determine if the vehicle was moving, braking, stationary, or reversing.

        Fig 4: Connecting Intelligent Tester To Data Link Connector
        G04473318Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. CHECK DLC3 

    The HV control ECU uses the ISO 15765-4 communication protocol. The terminal arrangement of the DLC3 complies with ISO 15031-03 and matches the ISO 15765-4 format.

    Fig 5: Identifying DLC3 Terminals
    G04473319Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    DLC3 TERMINALS REFERENCE

    Symbol Terminal No. Name Reference Terminal Result Condition
    SIL 7 Bus "+" line 5 - Signal ground Pulse generation During transmission
    CG 4 Chassis ground Body ground 1 Ω or less Always
    SG 5 Signal ground Body ground 1 Ω or less Always
    BAT 16 Battery positive Body ground 11 to 14 V Always
    CANH 6 HIGH-level CAN bus line 14 - LOW-level CAN bus line 54 to 69 Ω Power switch OFF(1)
    CANH 6 HIGH-level CAN bus line 16 - Battery positive 1 MΩ or higher Power switch OFF(1)
    CANH 6 HIGH-level CAN bus line 4 - Chassis ground 200 Ω or higher Power switch OFF(1)
    CANL 14 LOW-level CAN bus line 16 - Battery positive 1 MΩ or higher Power switch OFF(1)
    CANL 14 LOW-level CAN bus line 4 - Chassis ground 200 Ω or higher Power switch OFF(1)
    (1) NOTICE: Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power switch, other switches or doors.

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

    HINT:

    If the display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the intelligent tester to the DLC3, turned the power switch ON (IG) and operated the tester, there is a problem on the vehicle side or tester side.

    • If communication is normal when the tester or scan tool is connected to another vehicle, inspect the DLC3 on the original vehicle.
    • If communication is still not possible when the tester or scan tool is connected to another vehicle, the problem is probably in the tester or scan tool itself, so consult the Service Department listed in its instruction manual.
  3. INSPECT AUXILIARY BATTERY 
    1. Measure the voltage of the auxiliary battery.

      Standard voltage: 11 to 14 V 

    2. Inspect the auxiliary battery, fusible links, wire harness, connectors and ground.
  4. CHECK MIL 
    1. The MIL illuminates when the power switch is turned ON (IG) and the "READY" light is OFF.

      If the MIL is not illuminated, troubleshoot the MIL circuit (see MIL CIRCUIT ).

      Fig 6: Identifying Malfunction Indicator Lamp
      G04473320Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. When the "READY" light turns on, the MIL should turn off.

      If the MIL remains on, the diagnosis system has detected a malfunction or abnormality in the system.

      Fig 7: Identifying Ready Light
      G04473321Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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