Diagnosis System
2TR-FE ENGINE CONTROL: SFI 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 (Engine Control Module) can then be read.
OBD II regulations require that the vehicle's on-board computer illuminate the MIL (Malfunction Indicator Lamp) on the instrument panel when the computer detects a malfunction in:
* (a) The emission control systems and components
* (b) The powertrain control components which affect vehicle emissions
* (c) The computer itself
In addition, the applicable DTCs (Diagnostic Trouble Codes) prescribed by SAE J2012 are stored in the ECM memory. If the malfunction does not recur in 3 consecutive trips, the MIL turns off automatically but the DTCs remain stored in the ECM memory.
To check DTCs, connect the Techstream to the DLC3. The Techstream displays DTCs, freeze frame data and a variety of engine data. The DTCs and freeze frame data can be cleared with the Techstream Freeze Frame Data.
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 communication between systems and simplification of the wire harness connections.
Since this system is equipped with CAN communication, connecting the Techstream is necessary to display any information from the ECM. Also, the communication between the Techstream and ECM uses CAN communication signals. When confirming DTCs and ECM data, connect the Techstream to the DLC3.
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 increase the system's ability to detect malfunctions, including intermittent problems, when simulating malfunction symptoms (Techstream only)
Check Mode Procedure.
3. 2 TRIP DETECTION LOGIC
When a malfunction is first detected, the DTC is temporarily stored in the ECM memory (1st trip). If the same malfunction is detected during the next subsequent driving cycle, the MIL is illuminated (2nd trip).
4. 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.
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 SAE J1962 and matches the ISO 15765-4 format.
HINT
*: 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.
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 ignition switch on and turn the Techstream ON.
If a communication failure message is displayed on the Techstream screen (on the Techstream: Unable to Connect to VIM), 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 impossible: The problem is probably with the Techstream itself. Consult the Service Department listed in the instruction manual.
6. BATTERY VOLTAGE
Standard voltage:
11 to 14 V
If the voltage is below 11 V, recharge the battery before proceeding.
7. MIL (Malfunction Indicator Lamp)
(a) The MIL is illuminated when the ignition switch is first turned to ON (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 a malfunction or abnormality in the system.
HINT
If the MIL is not illuminated when the ignition switch is first turned to ON, check the MIL circuit Testing and Inspection.
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 ignition switch to ON.
(c) Turn the Techstream ON.
(d) Clear the DTCs DTC Check / Clear.
(e) Turn the ignition switch off and wait for at least 30 seconds.
(f) Perform the DTC judgment driving pattern to run the DTC judgment.
(g) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
(h) Input the DTCs to be confirmed.
(i) Check the DTC judgment result.
