SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

• w/ Fuel Pump Control ECU Assembly:

  The fuel pump circuit consists of the ECM, fuel pump 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 ECU adjust the fuel pump operation speed.

• w/o Fuel Pump Control ECU Assembly:

  When the engine is cranked, the starter (ST NO. 1) relay drive signal output from the ignition or starter switch assembly*1 or certification ECU (smart key ECU assembly)*2 is input into the STA terminal of the ECM, and the NE signal generated by the crankshaft position sensor is also input into the NE+ terminal. The ECM interprets that the engine is cranked, and turns transistor Tr1 in the ECM internal circuit on. Current flows to the C/OPN (Circuit Opening) relay by turning Tr1 on. Then, the fuel pump operates.

  While the NE signal is input into the ECM with the engine running, the ECM turns Tr1 on continuously.

  *1: w/o entry and start system

  *2: w/ entry and start system

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1. PERFORM ACTIVE TEST USING GTS (CONTROL THE FUEL PUMP/SPEED)

   
   

   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 and ECT / Active Test / Control the Fuel Pump/Speed.

      
      Powertrain > Engine and ECT > Active Test

      Tester Display
      Control the Fuel Pump / Speed

   5. Check whether the fuel pump operating sound occurs when performing the Active Test on the GTS.

      Result
      Result Proceed to Fuel pump operating sound does not occur (w/ fuel pump control ECU assembly) A Fuel pump operating sound does not occur (w/o fuel pump control ECU assembly) B Fuel pump operating sound occurs (w/ fuel pump control ECU assembly) C Fuel pump operating sound occurs (w/o fuel pump control ECU assembly) D

   
   

   B

   CHECK TERMINAL VOLTAGE (POWER SOURCE OF C/OPN RELAY) Click here

   C

   PERFORM ACTIVE TEST USING GTS (CONTROL THE FUEL PUMP DUTY) Click here

   D

   READ VALUE USING GTS (STARTER SIGNAL) Click here

   A

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

   
   
   1. 

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

      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) - Body ground Ignition switch ON 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   CHECK HARNESS AND CONNECTOR (EFI-MAIN RELAY - FUEL PUMP CONTROL ECU ASSEMBLY) Click here

   OK

3. 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

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

   
   

   1. Disconnect the fuel pump control ECU assembly connector.

   2. Disconnect the fuel pump 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 Always 10 kΩ or higher L20-5 (E) or L21-5 (FP-) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

5. INSPECT FUEL PUMP

   
   

   1. Inspect the fuel pump.

      Click here

      Tech Tips

      Perform "Inspection After Repair" after replacing the fuel pump.

      Click here

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE FUEL PUMP Click here

   OK

6. 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) - A50-21 (FPC) Always Below 1 Ω L21-2 (FPC) or A50-21 (FPC) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

7. REPLACE FUEL PUMP CONTROL ECU ASSEMBLY

   
   

   1. Replace the fuel pump control ECU assembly.

      for Sedan: Click here

      for Wagon: Click here

      for Hatchback: Click here

      Result
      Proceed to NEXT

   
   

   NEXT

8. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

   
   

   1. Check the fuel pump operation.

      OK
      Malfunction has been repaired successfully.

      Result
      Proceed to OK NG

   
   

   OK

   END

   NG

   REPLACE ECM Click here

9. CHECK HARNESS AND CONNECTOR (EFI-MAIN RELAY - FUEL PUMP CONTROL ECU ASSEMBLY)

   
   

   1. Remove the EFI-MAIN 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 relay) - L21-1 (+B) Always Below 1 Ω 3 (EFI-MAIN relay) or L21-1 (+B) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   GO TO ECM POWER SOURCE CIRCUIT Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

10. CHECK TERMINAL VOLTAGE (POWER SOURCE OF C/OPN RELAY)

    
    
    1. 

       *1	Engine Room Relay Block and Junction Block Assembly
       *2	C/OPN Relay

       Remove the C/OPN relay from the engine room relay block and junction block assembly.

    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 1 (C/OPN relay) - Body ground Ignition switch ON 11 to 14 V

       Result
       Proceed to OK NG

    
    

    NG

    CHECK HARNESS AND CONNECTOR (C/OPN RELAY - IG2 RELAY) Click here

    OK

11. INSPECT C/OPN RELAY

    
    

    1. Inspect the C/OPN relay.

       Click here

       Result
       Proceed to OK NG

    
    

    NG

    REPLACE C/OPN RELAY

    OK

12. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - ECM)

    
    

    1. Remove the C/OPN relay from the engine room relay block and junction block assembly.

    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 2 (C/OPN relay) - A50-21 (FC) Always Below 1 Ω 2 (C/OPN relay) or A50-21 (FC) - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

13. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - FUEL PUMP)

    
    

    1. Remove the C/OPN relay from the engine room relay block and junction block assembly.

    2. Disconnect the fuel pump connector.

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

       Standard Resistance
       Tester Connection Condition Specified Condition 3 (C/OPN relay) - L20-4 (B) Always Below 1 Ω 3 (C/OPN relay) or L20-4 (B) - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

14. CHECK HARNESS AND CONNECTOR (FUEL PUMP - BODY GROUND)

    
    

    1. Disconnect the fuel pump connector.

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

       Standard Resistance
       Tester Connection Condition Specified Condition L20-5 (E) - Body ground Always Below 1 Ω

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

15. INSPECT FUEL PUMP

    
    

    1. Inspect the fuel pump.

       Click here

       Tech Tips

       Perform "Inspection After Repair" after replacing the fuel pump.

       Click here

       Result
       Proceed to OK NG

    
    

    NG

    REPLACE FUEL PUMP Click here

    OK

16. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - EFI-MAIN RELAY)

    
    

    1. Remove the C/OPN relay and EFI-MAIN 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 5 (C/OPN relay) - 3 (EFI-MAIN relay) Always Below 1 Ω 5 (C/OPN relay) or 3 (EFI-MAIN relay) - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    OK

    GO TO ECM POWER SOURCE CIRCUIT Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

17. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - IG2 RELAY)

    
    

    1. Remove the C/OPN relay and IG2 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 1 (C/OPN relay) - 5 (IG2 relay) Always Below 1 Ω 1 (C/OPN relay) or 5 (IG2 relay) - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    OK

    GO TO ECM POWER SOURCE CIRCUIT Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

18. PERFORM ACTIVE TEST USING GTS (CONTROL THE FUEL PUMP DUTY)

    
    

    1. Remove the fuel suction tube with pump and gauge assembly.

       Click here

    2. Clean the fuel suction with pump and gauge tube assembly to completely remove any remaining fuel.

    3. Remove the fuel pump.

       Click here

    4. Connect the fuel pump and fuel suction with pump and gauge tube assembly connectors.

       Note

       Confirm that no fuel remains inside or on the outside of the fuel pump.

    5. Connect the GTS to the DLC3.

    6. Turn the ignition switch to ON.

    7. Turn the GTS on.

    8. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump Duty.

       
       Powertrain > Engine and ECT > Active Test

       Tester Display
       Control the Fuel Pump Duty

    9. 

       *a	Component with harness connected (Fuel Pump)

       Operate the fuel pump 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 1 - 2 Fuel pump control duty: 25% 3.4 to 4.1 V Fuel pump control duty: 80% 10.0 to 12.5 V

    10. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump / Speed.

        
        Powertrain > Engine and ECT > Active Test

        Tester Display
        Control the Fuel Pump / Speed

    11. Operate the fuel pump 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 1 - 2 ON (Fuel pump control duty: 90%) 10.2 to 14.0 V

        Tech Tips

        
        

        • Be sure to measure the voltage with the all 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

    REPLACE FUEL PUMP CONTROL ECU ASSEMBLY Click here

    OK

19. 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) - A50-21 (FPC) Always Below 1 Ω L21-2 (FPC) or A50-21 (FPC) - Body ground Always 10 kΩ or higher

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

20. REPLACE FUEL PUMP

    
    

    1. Replace the fuel pump.

       Click here

       Tech Tips

       Perform "Inspection After Repair" after replacing the fuel pump.

       Click here

       Result
       Proceed to NEXT

    
    

    NEXT

21. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

    
    

    1. Check the fuel pump operation.

       OK
       Malfunction has been repaired successfully.

       Result
       Proceed to OK NG

    
    

    OK

    END

    NG

    REPLACE ECM Click here

22. REPLACE FUEL PUMP CONTROL ECU ASSEMBLY

    
    

    1. Replace the fuel pump control ECU assembly.

       for Sedan: Click here

       for Wagon: Click here

       for Hatchback: Click here

       Result
       Proceed to NEXT

    
    

    NEXT

    GO TO STEP 21 Click here

23. READ VALUE USING GTS (STARTER SIGNAL)

    
    

    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 and ECT / Data List / All Data / Starter Signal.

       
       Powertrain > Engine and ECT > Data List

       Tester Display
       Starter Signal

    5. Check the result when the ignition switch is ON and the engine starts.

       OK
       Condition Starter Signal Ignition switch ON OFF Engine Started ON

       Result
       Proceed to OK NG

    
    

    NG

    CHECK STARTER SIGNAL CIRCUIT Click here

    OK

24. READ VALUE USING GTS (ENGINE SPEED)

    
    

    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 and ECT / Data List / All Data / Engine Speed.

       
       Powertrain > Engine and ECT > Data List

       Tester Display
       Engine Speed

    5. Read the values displayed on the GTS while cranking.

       OK
       Values are displayed continuously.

       Result
       Proceed to OK NG

    
    

    OK

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

    NG

    CHECK CRANKSHAFT POSITION SENSOR CIRCUIT Click here