SFI SYSTEM ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned on (IG), the battery voltage is applied to terminal IGSW of the ECM. The ECM MREL output signal causes a current to flow to the coil, closing the contacts of the EFI relay and supplying power to terminal +B and +B2 of the ECM.

If the ignition switch is turned off, the ECM holds the EFI relay ON for a maximum of 2 seconds to allow for the initial setting of the throttle valve.

INSPECTION PROCEDURE

PROCEDURE

1. Click here

   INSPECT ECM (+B AND +B2 VOLTAGE)

   
   
   1. 

      Turn the ignition switch on (IG).

   2. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      Tester Connection Switch Condition Specified Condition D31-1 (+B) - B3-1 (E1) Ignition switch on (IG) 9 to 14 V D31-2 (+B2) - B3-1 (E1) Ignition switch on (IG) 9 to 14 V

   
   
   • OKClick here
   • NGClick here
2. Click here

   CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

   
   
   1. 

      Disconnect the ECM connector.

   2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Check for open
      Tester Connection Condition Specified Condition B3-1 (E1) - Body ground Always Below 1 Ω

   3. Reconnect the ECM connector.

   
   
   • OKClick here
   • NGClick here
3. Click here

   INSPECT ECM (MREL VOLTAGE)

   
   
   1. 

      Turn the ignition switch on (IG).

   2. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      Tester Connection Switch Condition Specified Condition D31-8 (MREL) - B3-1 (E1) Ignition switch on (IG) 9 to 14 V

   
   
   • OKClick here
   • NGClick here
4. Click here

   CHECK FUSE (EFI MAIN AND EFI NO. 2 FUSE)

   
   
   1. 

      Remove the EFI MAIN and EFI No. 2 fuse from the engine room relay block.

   2. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition EFI MAIN fuse Always Below 1 Ω EFI No. 2 fuse Always Below 1 Ω

   3. Reinstall the fuses.

   
   
   • OKClick here
   • NGClick here
5. Click here

   INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (EFI RELAY)

   
   

   1. Inspect the EFI relay (Click here).

   
   
   • OKClick here
   • NGClick here
6. Click here

   CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - ECM, EFI RELAY - BODY GROUND)

   
   
   1. 

      Remove the engine room junction block from the engine room relay block.

   2. Disconnect the ECM connector.

   3. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Check for open
      Tester Connection Condition Specified Condition 2E-9 (EFI relay terminal) - D31-8 (MREL) Always Below 1 Ω 2E-10 (EFI relay terminal) - Body ground Always Below 1 Ω
      Check for short
      Tester Connection Condition Specified Condition 2E-9 (EFI relay terminal) or D31-8 (MREL) - Body ground Always 10 kΩ or higher

   4. Reinstall the engine room junction block.

   5. Reconnect the ECM connector.

   
   
   • OKClick here
   • NGClick here
7. Click here

   CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - ECM)

   
   
   1. 

      Remove the engine room junction block from the engine room relay block.

   2. Disconnect the ECM connector.

   3. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Check for open
      Tester Connection Condition Specified Condition 2E-6 (EFI relay terminal) - D31-1 (+B) Always Below 1 Ω 2E-6 (EFI relay terminal) - D31-2 (+B2) Always Below 1 Ω
      Check for short
      Tester Connection Condition Specified Condition 2E-6 (EFI relay terminal) or D31-1 (+B) - Body ground Always 10 kΩ or higher 2E-6 (EFI relay terminal) or D31-2 (+B2) - Body ground Always 10 kΩ or higher

   4. Reinstall the engine room junction block.

   5. Reconnect the ECM connector.

   
   
   • OKClick here
   • NGClick here
8. Click here

   INSPECT ECM (IGSW VOLTAGE)

   
   
   1. 

      Turn the ignition switch on (IG).

   2. Measure the voltage according to the value(s) in the table below.

      Standard voltage
      Tester Connection Switch Condition Specified Condition D31-9 (IGSW) - B3-1 (E1) Ignition switch on (IG) 9 to 14 V

   
   
   • OKClick here
   • NGClick here
9. Click here

   CHECK HARNESS AND CONNECTOR (ECM - IG2 RELAY)

   
   
   1. 

      Remove the IG2 relay from the engine room relay block.

   2. Disconnect the ECM connector.

   3. Measure the resistance according to the value(s) in the table below.

      Standard resistance
      Tester Connection Condition Specified Condition IG2 relay terminal 3 - D31-9 (IGSW) Always Below 1 Ω

   4. Reconnect the ECM connector.

   5. Reinstall the IG2 relay.

   
   
   • OKClick here
   • NGClick here
10. Click here

    INSPECT IG2 RELAY

    
    
    1. 

       Remove the IG2 relay from the engine room relay block.

    2. Measure the resistance according to the value(s) in the table below.

       Standard resistance
       Tester Connection Condition Specified Condition 3 - 5 When no battery voltage applied to terminals 1 and 2 10 kΩ or higher When battery voltage applied to terminals 1 and 2 Below 1 Ω

    3. Reinstall the IG2 relay.

    
    
    • OKClick here
    • NGClick here
11. Click here

    CHECK HARNESS AND CONNECTOR (IG2 RELAY POWER SOURCE)

    
    
    1. 

       Remove the IG2 relay from the engine room relay block.

    2. Turn the ignition switch on (IG)

    3. Measure the voltage according to the value(s) in the table below.

       Standard voltage
       Tester Connection Switch Condition Specified Condition 5 - Body ground Ignition switch on (IG) 9 to 14 V

    4. Reinstall the IG2 relay.

    
    
    • OKClick here
    • NGClick here
12. Click here

    CHECK HARNESS AND CONNECTOR (IG2 RELAY - BODY GROUND)

    
    
    1. 

       Remove the IG2 relay from the engine room relay block.

    2. Measure the resistance according to the value(s) in the table below.

       Standard resistance
       Tester Connection Condition Specified Condition 2 - Body ground Always Below 1 Ω

    3. Reinstall the IG2 relay.

       Result
       Result Proceed to NG A OK (w/o Smart entry and star system) B OK (w/ Smart entry and star system) C

    
    
    • AClick here
    • BClick here
    • CClick here
13. Click here

    CHECK FUSE (IG2 FUSE)

    
    
    1. 

       Remove the IG2 fuse from the engine room relay block.

    2. Measure the resistance according to the value(s) in the table below.

       Standard resistance
       Tester Connection Condition Specified Condition IG2 fuse Always Below 1 Ω

    3. Reinstall the IG2 fuse

    
    
    • OKClick here
    • NGClick here
14. Click here

    CHECK FUSE (IGN FUSE)

    
    
    1. 

       Remove the IGN fuse from the instrument panel junction block.

    2. Measure the resistance according to the value(s) in the table below.

       Standard resistance
       Tester Connection Condition Specified Condition IGN fuse Always Below 1 Ω

    3. Reinstall the IGN fuse.

    
    
    • OKClick here
    • NGClick here
15. Click here

    CHECK HARNESS AND CONNECTOR (IGNITION SWITCH - IG2 RELAY)

    
    
    1. 

       Remove the IG2 relay from the engine room relay block.

    2. Disconnect the ignition switch connector.

    3. Measure the resistance according to the value(s) in the table below.

       Standard resistance
       Check for open
       Tester Connection Condition Specified Condition D21-6 (IG2) - IG2 relay terminal 1 Always Below 1 Ω
       Check for short
       Tester Connection Condition Specified Condition D21-6 (IG2) or IG2 relay terminal 1 - Body ground Always 10 kΩ or higher

    4. Reinstall the IG2 relay.

    5. Reconnect the ignition switch connector.

    
    
    • OKClick here
    • NGClick here
16. Click here

    INSPECT IGNITION SWITCH

    
    

    1. Inspect the ignition or starter switch assembly (Click here).

    
    
    • OKClick here
    • NGClick here
17. Click here

    CHECK HARNESS AND CONNECTOR (IG2 RELAY - MAIN BODY ECU, IG2 RELAY - BODY GROUND)

    
    
    1. 

       Remove the IG2 relay from the engine room relay block.

    2. Remove the instrument panel junction block (main body ECU).

    3. Measure the resistance according to the value(s) in the table below.

       Standard resistance (Check for open)
       Tester Connection Condition Specified Condition IG2 relay terminal (1) - D6-11 (IG2D) Always Below 1 Ω IG2 relay terminal (2) - Body ground Always Below 1 Ω

       Standard resistance (Check for short)
       Tester Connection Condition Specified Condition D6-11 (IG2D) - Body ground Always 10 kΩ or higher

    4. Reinstall the IG2 relay.

    5. Reconnect the main body ECU connector.

    
    
    • OKClick here
    • NGClick here
18. Click here

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

19. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BODY GROUND)

20. Click here

    REPLACE FUSE (EFI MAIN OR EFI NO. 2 FUSE)

21. Click here

    REPLACE RELAY (EFI RELAY)Click here

22. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI MAIN RELAY - ECM)

23. Click here

    REPLACE ECMClick here

24. Click here

    REPLACE IG2 RELAY

25. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BODY GROUND)

26. Click here

    REPLACE FUSE (IG2 FUSE)

27. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - BATTERY)

28. Click here

    REPLACE FUSE (IGN FUSE)

29. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IG2 RELAY - ECM)

30. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH - IG2 RELAY)

31. Click here

    REPLACE IGNITION SWITCHClick here

32. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH - BATTERY)

33. Click here

    CHECK SMART ENTRY AND START SYSTEMClick here

34. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR

35. Click here

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI MAIN RELAY - EFI MAIN FUSE)