SFI SYSTEM > DIAGNOSIS SYSTEM

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1. The emission control system components.
   

2. The powertrain control components (which affect vehicle emissions).
   

3. 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 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 intelligent tester or OBD 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 by using the scan tool (Click here).
   

1. When troubleshooting a Multiplex On-Board Diagnostic (M-OBD) vehicle, the vehicle must be connected to the intelligent tester. Various data output from the ECM can then be read.
   
2. OBD regulations require that the vehicle on-board computer illuminate the MIL on the instrument panel when the computer detects a malfunction in:
   
1. The emission control system/components.
   
2. The powertrain control components (which affect vehicle emissions).
   
3. The computer.
   
3. In addition, the applicable DTCs 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 recorded in the ECM memory.
   

1. 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).
   

1. Check DLC3 (Click here).
   

1. 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 running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
   

Standard voltage:

11 to 16 V

1. If voltage is below 11 V, replace or recharge the auxiliary battery.
   

1. The MIL illuminates when the power switch is first turned on (IG) (the engine is not running).
   

2. 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 does not illuminate when the power switch is first turned to on (IG), check the MIL circuit (Click here).

HINT:

1. With "ALL READINESS", you can check whether or not the DTC judgment has been completed by using the intelligent tester.
   
2. You should check "ALL READINESS" after simulating malfunction symptoms or for validation after finishing repairs.
   

1. Connect the intelligent tester to the DLC3.
   

2. Turn the power switch on (IG).
   

3. Turn the tester on.
   

4. Clear the DTCs (Click here).
   

5. Turn the power switch off and wait for 30 seconds.
   

6. Turn the power switch on (IG) and turn the tester on.
   

7. Perform the DTC judgment driving pattern to run the DTC judgment.
   

8. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
   

9. Input the DTCs to be confirmed.
   

10. Check the DTC judgment result.
    
    

    Intelligent tester 

    Tester 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 the DTC enabling conditions
    UNKNOWN	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU's memory limit