M20F-FXS, M20G-FXS ENGINE CONTROL SFI SYSTEM DIAGNOSIS SYSTEM
CHINA NATIONWIDE STAGE 6
When troubleshooting On-Board Diagnostic (OBD) vehicles, a scan tool (complying with ISO 15765-4) must be connected to the vehicle. Various data output from the vehicle's ECM can then be read.
OBD regulations require that the vehicle's on-board computer illuminate 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 stored in the ECM memory. If the malfunction does not reoccur in 3 consecutive trips, the MIL turns off automatically but the DTCs remain stored in the ECM memory.
To check DTCs, connect the GTS or scan tool to the Data Link Connector 3 (DLC3) of the vehicle.
The scan tool displays DTCs, the Freeze Frame Data and a variety of engine data.
The DTCs and Freeze Frame Data can be cleared using the scan tool.
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 (GTS only).
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 drive cycle, the MIL is illuminated (2nd trip).
DLC3 (Data Link Connector 3)
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 moving or stationary, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
AUXILIARY BATTERY VOLTAGE
- Standard Voltage:
11 to 16 V
If the voltage is less than 11 V, recharge or replace the auxiliary battery.
MIL (Malfunction Indicator Lamp)
The MIL is illuminated when the ignition switch is to ON (when the engine is not running).
The MIL will turn off when the ignition switch is to ON (READY). If the MIL remains illuminated, the diagnosis system has detected a malfunction or abnormality in the system.
- HINT:
-
If the MIL does not illuminate when the ignition switch is to ON, check the MIL circuit.
ALL READINESS
- HINT:
- ·
With "All Readiness", you can use the GTS to check whether or not DTC judgment has been completed.
·You should check "All Readiness" after simulating malfunction symptoms or for validation after finishing repairs.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Clear the DTCs.
- Powertrain > Engine > Clear DTCs
- 50002 372
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON.
Turn the GTS on.
Perform the DTC judgment driving pattern to run the DTC judgment.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
- Powertrain > Engine > Utility
-
Tester Display All Readiness - 50005 372 20
Input the DTCs to be confirmed.
Check the DTC judgment result.
| GTS Display | Description |
|---|---|
| NORMAL | ·
DTC judgment completed ·
System normal |
| ABNORMAL | ·
DTC judgment completed ·
System abnormal |
| INCOMPLETE | ·
DTC judgment not completed ·
Perform the driving pattern after confirming DTC enabling conditions |
DIAGNOSIS RELATED INFORMATION
- HINT:
- ·
If the detection conditions of certain DTCs are met before a malfunction can be confirmed, the ECM will store Diagnosis Related Information. Vehicle condition information from when the detection conditions were met can be checked using the Diagnosis Related Information. Diagnosis Related Information should be used as a reference only, and should not be relied upon solely when determining whether a part is faulty or not.
·Clearing DTCs will also clear Diagnosis Related Information.
·DTCs and Diagnosis Related Information are saved in the GTS at the same time.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine / Utility / Diagnosis Related Information.
- Powertrain > Engine > Utility
-
Tester Display Diagnosis Related Information - 50005 372 56
Select a Diagnosis Related Information item to display its details.