ECD SYSTEM DIAGNOSIS SYSTEM


  1. EURO-OBD (EUROPE)

    A01KHAYE03

    When troubleshooting Europe On-Board Diagnostic (Euro-OBD) vehicles, the vehicle must be connected to an OBD scan tool (complying with ISO 15765-4). Various data output from the vehicle's ECM can then be read.

    Euro-OBD regulations require that the vehicle's on-board computer illuminate the Malfunction Indicator Lamp (MIL) on the instrument panel when the computer detects a malfunction in:


    1. The emission control system components

    2. The powertrain control components (which affect vehicle emissions)

    3. A01KI6BE07
      Text in Illustration
      *1 Intelligent Tester
      *2 DLC3

      The computer

      In addition, if the applicable Diagnostic Trouble Codes (DTCs) prescribed by ISO 15765-4 are recorded in the ECM memory. If the malfunction does not reoccur in 3 consecutive trips, the MIL turns off automatically but the DTCs remain recorded in the ECM memory.

      To check DTCs, connect an intelligent tester or OBD scan tool to the Data Link Connector 3 (DLC3) of the vehicle.

      The scan tool displays DTCs, the freeze frame data and a variety of engine data.

      The DTCs and freeze frame data can be erased the scan tool Click here.

  2. M-OBD (EXCEPT EUROPEAN SPEC.)

    A01KHAYE03

    When troubleshooting Multiplex On-Board Diagnostic (M-OBD) vehicle, the vehicle must be connected to the intelligent tester. Various data output from the ECM can then be read.

    OBD regulations require that the vehicle's on-board computer illuminate the MIL on the instrument panel when the computer detects a malfunction in:


    1. The emission control system/components

    2. The powertrain control components (which affect vehicle emissions)

    3. The computer

      In addition, the applicable DTCs are recorded in the ECM memory. If the malfunction does not recur in 3 consecutive trips, the MIL turns off automatically but the DTCs remain recorded in the ECM memory.

  3. NORMAL MODE AND CHECK MODE

    The diagnosis system operates in "normal mode" during normal vehicle use. In normal mode, "2 trip detection logic" is used to ensure accurate detection of malfunctions. "Check mode" is also available to technicians as an option. In check mode, "1 trip detection logic" is used for simulating malfunction symptoms and increasing the system's ability to detect malfunctions, including intermittent malfunctions Click here.

  4. 2 TRIP DETECTION LOGIC

    When a malfunction is first detected, the malfunction is temporarily stored in the ECM memory (1st trip). If the same malfunction is detected during the subsequent drive cycle, the MIL is illuminated (2nd trip).

  5. FREEZE FRAME DATA

    Freeze frame data records the engine conditions (fuel system, calculated engine load, engine coolant temperature, fuel trim, engine speed, vehicle speed, etc.) when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

  6. CHECK DLC3

    A01KGH1E16

    The ECM uses ISO 15765-4 for communication. The terminal arrangement of the DLC3 complies with ISO 15031-3 and matches the ISO 15765-4 format.

    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 Ω
    SG (5) - Body ground Signal ground Always Below 1 Ω
    BAT (16) - Body ground Battery positive Always 11 to 14 V
    CANH (6) - CANL (14) CAN bus line

    Ignition switch OFF*

    		54 to 69 Ω
    CANH (6) - CG (4) HIGH-level CAN bus line

    Ignition switch OFF*

    		200 Ω or higher
    CANL (14) - CG (4) LOW-level CAN bus line

    Ignition switch OFF*

    		200 Ω or higher
    CANH (6) - BAT (16) HIGH-level CAN bus line

    Ignition switch OFF*

    		6 kΩ or higher
    CANL (14) - BAT (16) LOW-level CAN bus line

    Ignition switch OFF*

    		6 kΩ or higher

    Note

    *: 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.

    Tech Tips

    Connect the cable of the intelligent tester to the DLC3, turn the ignition switch ON and attempt to use the intelligent tester. If the display indicates that a communication error has occurred, 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 on 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.

  7. INSPECT BATTERY VOLTAGE

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

  8. CHECK MIL

    A01KGHQ

    1. The MIL illuminates when the ignition switch is turned ON and the engine is not running.

      Tech Tips

      If the MIL is not illuminated, check the MIL circuit (refer to MIL CIRCUIT on page Click here).

    2. When the engine is started, the MIL should turn off. If the lamp remains illuminated, the diagnosis system has detected a malfunction or abnormality in the system.