AUTOMATIC TRANSMISSION SYSTEM DIAGNOSIS SYSTEM


  1. OBD II


    1. When troubleshooting OBD II (On-Board Diagnostics) vehicles, an OBD II scan tool (complying with SAE J1987) must be connected to the DLC3 (Data Link Connector 3) of the vehicle. Various data in the vehicle ECM (Engine Control Module) can be then read.

    2. A01FGT0

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


      • The emission control system components.

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

      • The computer itself.

    3. In addition, the applicable DTCs prescribed by SAE J2012 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.

      To check for DTCs, connect the GTS to the DLC3. The GTS displays DTCs, freeze frame data, and a variety of the engine data. The DTCs and freeze frame data can be cleared with the GTS. In order to enhance OBD function on vehicles and develop the off-board diagnosis system, Controller Area Network (CAN) communication is used in this system. CAN is a network which uses a pair of data transmission lines spanning multiple computers and sensors. It allows for high speed communications between the systems and simplification of the wire harness connections.

  2. EURO-OBD


    1. 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 ECM can then be read.

    2. A01FGT0

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


      • The emission control system/components

      • The powertrain control components which affect vehicle emissions

      • The computer

      In addition, the applicable Diagnostic Trouble Codes (DTCs) prescribed by ISO 15765-4 are stored in the ECM memory.

      If the malfunction does not recur in 3 consecutive trips, the MIL goes off automatically but the DTCs remain stored in the ECM memory.

    3. To check DTCs, connect the GTS or OBD scan tool to the Data Link Connector 3 (DLC3) of the vehicle. The scan tool displays DTCs, freeze frame data and a variety of engine data.

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

  3. M-OBD


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

    2. A01FGT0

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


      • The emission control system/components

      • The powertrain control components which affect vehicle emissions

      • The computer

      In addition, the applicable Diagnostic Trouble Codes (DTCs) prescribed by ISO 15765-4 are stored in the ECM memory.

      If the malfunction does not recur in 3 consecutive trips, the MIL goes off automatically but the DTCs remain stored in the ECM memory.

  4. 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 as an option for technicians. In check mode, 1 trip detection logic is used for duplicating malfunction symptoms and increasing the system's ability to detect malfunctions, including intermittent problems (the GTS only).

  5. 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 driving cycle, the MIL is illuminated (2nd trip).

  6. FREEZE FRAME DATA


    • The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

  7. DLC3 (Data Link Connector 3)


    1. Check the DLC3 Click here.

  8. BATTERY VOLTAGE


    • If voltage is below 11 V, replace or recharge the battery before proceeding to the next step.

  9. MIL (Malfunction Indicator Lamp)


    1. The MIL illuminates when the engine switch is first turned on (IG) (the engine is not running).

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

      Tech Tips

      If the MIL does not illuminate when the engine switch is first turned on (IG), check the MIL circuit Click here.