SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

The fuel pump circuit consists of the ECM, fuel pump (for low pressure side) and fuel pump control ECU assembly (which operates the fuel pump). Based on the engine output, the ECM determines the fuel pump speed. The speed is then converted to a duty signal and sent to the fuel pump control ECU assembly. Based on the signal sent from the ECM, the fuel pump control ECU adjust the fuel pump operation speed.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1. PERFORM ACTIVE TEST USING GTS (ACTIVATE THE CIRCUIT RELAY)

   
   

   1. Connect the GTS to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the GTS on.

   4. Enter the following menus: Powertrain / Engine / Active Test / Activate the Circuit Relay.

      
      Powertrain > Engine > Active Test

      Tester Display
      Activate the Circuit Relay

   5. Check whether operating sounds can be heard while operating the fuel pump (for low pressure side) using the GTS.

      OK
      Operating sounds can be heard from the fuel pump (for low pressure side).

      Result
      Proceed to OK NG

   
   

   NG

   CHECK TERMINAL VOLTAGE (POWER SOURCE OF FUEL PUMP CONTROL ECU ASSEMBLY) Click here

   OK

2. PERFORM ACTIVE TEST USING GTS (CONTROL THE FUEL PUMP DUTY RATIO, ACTIVATE THE CIRCUIT RELAY)

   

   *a	Component with harness connected (Fuel Pump [for Low Pressure Side])

   
   

   1. Remove the fuel pump (for low pressure side) from the fuel tank assembly.

      Click here

   2. Clean the fuel pump to completely remove any remaining fuel.

   3. Connect the fuel pump connector.

      CAUTION:

      Make sure that there is no fuel remaining inside or on the outside of the fuel pump.

   4. Connect the GTS to the DLC3.

   5. Turn the ignition switch to ON.

   6. Turn the GTS on.

   7. Enter the following menus: Powertrain / Engine / Active Test / Control the Fuel Pump Duty Ratio.

      
      Powertrain > Engine > Active Test

      Tester Display
      Control the Fuel Pump Duty Ratio

   8. Operate the fuel pump (for low pressure side) using the Active Test function and measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection GTS Operation Specified Condition 2 - 1 Fuel pump duty ratio: 25% 3.2 to 4.05 V Fuel pump duty ratio: 80% 8.8 to 12.5 V

   9. Enter the following menus: Powertrain / Engine / Active Test / Activate the Circuit Relay.

      
      Powertrain > Engine > Active Test

      Tester Display
      Activate the Circuit Relay

   10. Operate the fuel pump (for low pressure side) using the Active Test function and measure the voltage according to the value(s) in the table below.

       Standard Voltage
       Tester Connection GTS Operation Specified Condition 2 - 1 ON (Fuel pump duty ratio: 90%) 9.0 to 14.0 V

       Tech Tips

       
       

       • Be sure to measure the voltage with all the connectors connected.

       • Before performing this inspection, check that the battery voltage is between 11 and 14 V (not depleted).

       Result
       Proceed to OK NG

   
   

   NG

   GO TO STEP 8 Click here

   OK

3. INSPECT FUEL PUMP (FOR LOW PRESSURE SIDE)

   
   

   1. Inspect the fuel pump (for low pressure side).

      Click here

      Result
      Proceed to OK NG

   
   

   OK

   END

   NG

4. CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU ASSEMBLY - ECM)

   
   

   1. Disconnect the fuel pump control ECU assembly connector.

   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 L21-2 (FPC) - A173-21 (FPC) Always Below 1 Ω L21-2 (FPC) or A173-21 (FPC) - Body ground and other terminals Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

5. REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE)

   
   

   1. Replace the fuel pump (for low pressure side).

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel pump (for low pressure side).

      Click here

      Result
      Proceed to NEXT

   
   

   NEXT

6. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

   
   

   1. Check the fuel pump operation.

      Click here

      OK
      Malfunction has been repaired successfully.

      Result
      Proceed to OK NG

   
   

   OK

   END

   NG

   PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

7. CHECK TERMINAL VOLTAGE (POWER SOURCE OF FUEL PUMP CONTROL ECU ASSEMBLY)

   

   *a	Front view of wire harness connector (to Fuel Pump Control ECU Assembly)

   
   

   1. Disconnect the fuel pump control ECU assembly connector.

   2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Condition Specified Condition L21-1 (+B) - L21-4 (E) Ignition switch ON 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU ASSEMBLY - BODY GROUND) Click here

   OK

8. INSPECT FUEL PUMP (FOR LOW PRESSURE SIDE)

   
   

   1. Inspect the fuel pump (for low pressure side).

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel pump (for low pressure side).

      Click here

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE FUEL PUMP (FOR LOW PRESSURE SIDE) Click here

   OK

9. CHECK HARNESS AND CONNECTOR (FUEL PUMP (FOR LOW PRESSURE SIDE) - FUEL PUMP CONTROL ECU ASSEMBLY)

   
   

   1. Disconnect the fuel pump (for low pressure side) connector.

   2. Disconnect the fuel pump control ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition L20-4 (B) - L21-6 (FP) Always Below 1 Ω L20-5 (E) - L21-5 (FP-) Always Below 1 Ω L20-4 (B) or L21-6 (FP) - Body ground and other terminals Always 10 kΩ or higher L20-5 (E) or L21-5 (FP-) - Body ground and other terminals Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

10. CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU ASSEMBLY - ECM)

    
    

    1. Disconnect the fuel pump control ECU assembly connector.

    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 L21-2 (FPC) - A173-21 (FPC) Always Below 1 Ω L21-2 (FPC) or A173-21 (FPC) - Body ground and other terminals Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

11. REPLACE FUEL PUMP CONTROL ECU ASSEMBLY

    
    

    1. Replace the fuel pump control ECU assembly.

       for Hatchback: Click here

       for Wagon: Click here

       Result
       Proceed to NEXT

    
    

    NEXT

12. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

    
    

    1. Check the fuel pump operation.

       Click here

       OK
       Malfunction has been repaired successfully.

       Result
       Proceed to OK NG

    
    

    OK

    END

    NG

    REPLACE ECM Click here

13. CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU ASSEMBLY - BODY GROUND)

    
    

    1. Disconnect the fuel pump control ECU assembly connector.

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

       Standard Resistance
       Tester Connection Condition Specified Condition L21-4 (E) - Body ground Always Below 1 Ω

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

14. CHECK HARNESS AND CONNECTOR (FUEL PUMP CONTROL ECU ASSEMBLY - ECM)

    
    

    1. Disconnect the fuel pump control ECU assembly connector.

    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 L21-2 (FPC) - A173-21 (FPC) Always Below 1 Ω L21-2 (FPC) or A173-21 (FPC) - Body ground and other terminals Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

15. INSPECT EFI MAIN NO. 2 RELAY

    
    

    1. Inspect the EFI MAIN NO. 2 relay.

       Click here

       Result
       Proceed to OK NG

    
    

    NG

    REPLACE EFI MAIN NO. 2 RELAY

    OK

16. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY VOLTAGE)

    
    

    1. Remove the EFI MAIN NO. 2 relay from the engine room relay block and junction block assembly.

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

       Standard Voltage
       Tester Connection Condition Specified Condition 5 (EFI-MAIN NO. 2 relay) - Body ground Always 11 to 14 V

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI-MAIN NO. 2 RELAY)

    OK

17. CHECK HARNESS AND CONNECTOR (EFI MAIN NO. 2 RELAY - FUEL PUMP CONTROL ECU ASSEMBLY)

    
    

    1. Remove the EFI MAIN NO. 2 relay from the engine room relay block and junction block assembly.

    2. Disconnect the fuel pump control ECU assembly connector.

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

       Standard Resistance
       Tester Connection Condition Specified Condition 3 (EFI MAIN NO. 2 relay) - L21-1 (+B) Always Below 1 Ω 3 (EFI MAIN NO. 2 relay) or L21-1 (+B) - Body ground and other terminals Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

18. CHECK HARNESS AND CONNECTOR (EFI-MAIN RELAY - EFI MAIN NO. 2 RELAY)

    
    

    1. Remove the EFI MAIN NO. 2 and EFI-MAIN relays from the engine room relay block and junction block assembly.

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

       Standard Resistance
       Tester Connection Condition Specified Condition 3 (EFI-MAIN relay) - 1 (EFI MAIN NO. 2 relay) Always Below 1 Ω 3 (EFI-MAIN relay) or 1 (EFI MAIN NO. 2 relay) - Body ground and other terminals Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

19. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 2 RELAY - BODY GROUND)

    
    

    1. Remove the EFI MAIN NO. 2 relay from the engine room relay block and junction block assembly.

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

       Standard Resistance
       Tester Connection Condition Specified Condition 2 (EFI MAIN NO. 2 relay) - Body ground Always Below 1 Ω

       Result
       Proceed to OK NG

    
    

    OK

    CHECK ECM POWER SOURCE CIRCUIT Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR