EURO-OBD
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 illuminates the Malfunction Indicator Lamp (MIL) 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.
In addition, 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 the Intelligent Tester to the Data Link Connector 3 (DLC3) of the vehicle.
The scan tool displays DTCs, the freeze frame data and a variety of the engine data.
The DTCs and freeze frame data can be erased with the scan tool Click here.
M-OBD
When troubleshooting Multiplex On-Board Diagnostic (M- OBD) vehicles, 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 illuminates the MIL 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
In addition to, 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.
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 (Intelligent Tester only).
2-TRIP DETECTION LOGIC
When a malfunction is first detected, the malfunction is temporarily stored in the ECM memory (1st trip). If the ignition switch is turned OFF and then ON again, and the same malfunction is detected again, the MIL will illuminate.
FREEZE FRAME DATA
Freeze frame data records the engine conditions (fuel system, calculated 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 moving or stationary, 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.
DLC3 (Data Link Connector 3)
The vehicle's ECM uses the ISO 9141-2 (Euro-OBD)/ISO 14230 (M-OBD) communication protocol. The terminal arrangement of the DLC3 complies with ISO 15031-03 and matches the ISO 9141-2/ISO 14230 format.
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 screen displays UNABLE TO CONNECT TO VEHICLE, a problem exists in the vehicle side or the tester side.
If the communication is normal when the tool is connected to another vehicle, inspect the DLC3 on the original vehicle.
If the communication is still impossible when the tool is connected to another vehicle, the problem is probably in the tool itself. Consult the Service Department listed in the tool's instruction malfunction.
| 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 | 9 to 14 V | Always |
INSPECT BATTERY VOLTAGE
If voltage is below 11 V, replace the battery before proceeding.
CHECK MIL
Check that the MIL illuminates when turning the ignition switch ON.
If the MIL does not illuminate, there is a problem in the MIL circuit (w/ Secondary Air Injection System: Click here, w/o Secondary Air Injection System: Click here.
When the engine is started, the MIL should turn off.