SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

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 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 engine switch on (IG).

   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 using the GTS.

      OK
      Operating sounds can be heard from the fuel pump.

      Result
      Proceed to OK NG

   
   

   NG

   INSPECT FUEL PUMP CONTROL ECU ASSEMBLY (POWER SOURCE VOLTAGE) 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 engine switch on (IG).

   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 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 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 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 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 7 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. 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

5. 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

6. INSPECT FUEL PUMP CONTROL ECU ASSEMBLY (POWER SOURCE VOLTAGE)

   

   *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 engine switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition R121-1 (+B) - R121-4 (E) Engine switch on (IG) 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

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

   OK

7. 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

8. 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 R44-4 (B) - R121-5 (FP) Always Below 1 Ω R44-5 (E) - R121-6 (FP-) Always Below 1 Ω R44-4 (B) or R121-5 (FP) - Body ground and other terminals Always 10 kΩ or higher R44-5 (E) or R121-6 (FP-) - Body ground and other terminals Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

9. 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 R121-2 (FPC) - A78-21 (FPC) Always Below 1 Ω R121-2 (FPC) or A78-21 (FPC) - Body ground and other terminals Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

10. INSPECT ECM (FPC TERMINAL)

    

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

    
    

    1. Disconnect the fuel pump control ECU assembly connector.

    2. Connect the GTS to the DLC3.

    3. Turn the engine switch on (IG).

    4. Turn the GTS on.

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

       
       Powertrain > Engine > Active Test

       Tester Display
       Activate the Circuit Relay

    6. Operate the fuel pump control ECU assembly using the Active Test function and measure the resistance according to the value(s) in the table below.

       Standard Resistance
       Tester Connection Techstream Operation Specified Condition R121-2 (FPC) - Body ground Before Active Test → During Active Test Before Active Test: Resistance is stable → During Active Test: Resistance fluctuates*

       Tech Tips

       *: Using the Active Test, duty control of the transistors in the ECM will be performed. Due to the duty control, resistance of the FPC terminal will be unstable during the Active Test. If the resistance is stable before the Active Test and fluctuates while performing the Active Test, it can be determined that the transistor is operating. If the transistor does not operate during the Active Test, the ECM may be malfunctioning.

       Result
       Proceed to OK NG

    
    

    OK

    REPLACE FUEL PUMP CONTROL ECU ASSEMBLY

    NG

    REPLACE ECM Click here

11. 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 R121-4 (E) - Body ground Always Below 1 Ω

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

12. 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

13. CHECK TERMINAL VOLTAGE (POWER SOURCE VOLTAGE OF EFI-MAIN NO. 2 RELAY)

    

    *1	Engine Room Relay Block and Junction Block Assembly
    *2	EFI-MAIN NO. 2 Relay

    
    

    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 3 (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

14. 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 1 (EFI-MAIN NO. 2 relay) - Body ground Always Below 1 Ω

       Result
       Proceed to OK NG

    
    

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

15. CHECK HARNESS AND CONNECTOR (EFI-MAIN NO. 1 RELAY - EFI-MAIN NO. 2 RELAY)

    
    

    1. Remove the EFI-MAIN NO. 1, EFI-MAIN NO. 2 and EFI-MAIN NO. 3 relays from the engine room relay block and junction block assembly.

       Tech Tips

       Remove the EFI-MAIN NO. 3 relay connected between the checked terminals as the coil inside the relay influences the measurement value.

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

       Standard Resistance
       Tester Connection Condition Specified Condition 5 (EFI-MAIN NO. 1 relay) - 2 (EFI-MAIN NO. 2 relay) Always Below 1 Ω 5 (EFI-MAIN NO. 1 relay) or 2 (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

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

    
    

    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 connector.

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

       Standard Resistance
       Tester Connection Condition Specified Condition 5 (EFI-MAIN NO. 2 relay) - R121-1 (+B) Always Below 1 Ω 5 (EFI-MAIN NO. 2 relay) or R121-1 (+B) - Body ground and other terminals 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