Diagnosis System
2GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: DIAGNOSIS SYSTEM
DIAGNOSIS SYSTEM
1. DESCRIPTION
- When troubleshooting OBD II (On-Board Diagnostics) vehicles, the Techstream (complying with SAE J1987) must be connected to the DLC3 (Data Link Connector 3) of the vehicle. Various data in the vehicle's ECM can be then read.
- OBD II regulations require that the vehicle's on-board computer illuminates the MIL (Malfunction Indicator Lamp) on the combination meter when the computer detects a malfunction in:
1 The emission control systems components.
2 The power train control components (which affect vehicle emissions).
3 The computer itself.
- 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 Techstream to the DLC3. The tester displays DTCs, freeze frame data, and a variety of the engine data. The DTCs and freeze frame data can be erased with the Techstream. In order to enhance OBD function on vehicles and develop the Off-Board diagnosis system, CAN communication is introduced in this system (CAN: Controller Area Network). It minimizes the gap between technician skills and vehicle technology. CAN is a network, which uses a pair of data transmission lines, spanning multiple computers and sensors. It allows high speed communication between the systems and simplifies the wire harness connection. Since this system is equipped with the CAN communication, connecting the CAN VIM (VIM: Vehicle Interface Module) with the Techstream is necessary to display any information from the ECM. (Also the communication between the Techstream and the ECM uses CAN communication signals.) When confirming the DTCs and any data of the ECM, connect the CAN VIM between the DLC3 and the Techstream.
2. 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 simulating malfunction symptoms and increasing the system's ability to detect malfunctions, including intermittent problems (Techstream only).
3. 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 next subsequent drive cycle, the MIL is illuminated (2nd trip).
4. 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 malfunctions are 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.
5. DLC3 (Data link Connector 3)
- The vehicle's ECM uses the ISO 15765-4 for communication protocol. The terminal arrangement of the DLC3 complies with ISO 15031-3 and matches the ISO 15765-4 format.
NOTICE:
*: Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power switch, any other switches or the doors.
If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector.
HINT: The DLC3 is the interface prepared for reading various data from the vehicle's ECM. After connecting the cable of the Techstream, turn the power switch on (IG) and turn the Techstream on. If a communication failure message is displayed on the Techstream screen (on the Techstream: UNABLE TO CONNECT TO VEHICLE), a problem exists in either the vehicle or Techstream. In order to identify the location of the problem, connect the Techstream to another vehicle.
- If communication is normal: Inspect the DLC3 on the original vehicle.
- If communication is still not possible: The problem is probably in the Techstream itself. Consult the Service Department listed in the instruction manual.
6. BATTERY VOLTAGE
Battery Voltage:
11 to 14 V
- If voltage is below 11 V, replace or recharge the battery before proceeding.
7. MIL (Malfunction Indicator Lamp)
(a) The MIL is illuminated when the power switch is first turned on (IG) (the engine is not running).
(b) The MIL should turn off when the engine is started. If the MIL remains illuminated, the diagnosis system has detected malfunction or abnormality in the system.
HINT: If the MIL is not illuminated when the power switch is first turned on (IG), check the MIL circuit MIL Circuit.
8. ALL READINESS
HINT:
- With All Readiness you can check whether or not the DTC judgment has been completed by using the Techstream.
- You should check All Readiness after simulating malfunction symptoms or for validation after finishing repairs.
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs DTC Check / Clear.
(e) Perform the DTC judgment driving pattern to run the DTC judgment.
(f) Enter the following menus: Powertrain / Engine / Utility / All Readiness.
(g) Input the DTCs to be confirmed.
(h) Check the DTC judgment result.
Techstream:
