Система Ecd Система Диагностики
DESCRIPTION
NORMAL MODE AND CHECK MODE
2 TRIP DETECTION LOGIC
FREEZE FRAME DATA
CHECK DLC3
INSPECT BATTERY VOLTAGE
CHECK MIL
Система Ecd -- Система Диагностики |
When troubleshooting Multiplex OBD (M-OBD) vehicles, the vehicle must be connected to the intelligent tester. Various data output from the vehicle's Engine Control Module (ECM) can then be read.
The Malfunction Indicator Lamp (MIL) is illuminated when the vehicle's onboard computer detects a malfunction in the computer itself or in drive system components. In addition, the applicable Diagnostic Trouble Codes (DTCs) are recorded in the ECM memory (See page Нажмите здесь).
If the malfunction does not reoccur, the MIL stays illuminated until the ignition switch is turned off, and the MIL turns off when the engine is started. However, the DTCs remain stored in the ECM memory.
To check DTCs, connect the intelligent tester to the Data Link Connector 3 (DLC3) on the vehicle or connect terminals TC and CG of the DLC3 (DTCs will be output by the combination meter assembly).
| 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 when simulating malfunction symptoms to increase the system's ability to detect malfunctions, including intermittent malfunctions (See page Нажмите здесь).
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 next subsequent drive cycle, the MIL is illuminated (2nd trip).
Freeze frame data records the engine conditions (fuel system information, 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 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.
The vehicle's ECM uses the ISO 14230 (M-OBD) communication protocol. The terminal arrangement of the DLC3 complies with ISO 15031-03 and matches the ISO 14230 format.
Symbol (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
|
- УКАЗАНИЕ:
- Connect the cable of the intelligent tester to the DLC3, turn the ignition switch to 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.
If the voltage is below 11 V, recharge or replace the battery before proceeding.
- Battery voltage:
- 11 to 14 V
The MIL illuminates when the ignition switch is turned to ON and the engine is not running.
- УКАЗАНИЕ:
- If the MIL is not illuminated, check the MIL circuit (See page Нажмите здесь).
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.
