SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

When the engine is cranked, the ST NO. 1 relay drive signal is input to the STA terminal of the ECM, and NE signal generated by the crankshaft position sensor is also input to the NE+ terminal. Thus, the ECM interprets that the engine has been cranked, and turns the transistor in the ECM internal circuit on. The current flows to the C/OPN relay by turning the transistor on. Then, the fuel pump operates.

While the NE signal is input to the ECM with the engine running, the ECM turns the transistor on continuously.

WIRING DIAGRAM

A0030DNE01

CAUTION / NOTICE / HINT

Note

Inspect the fuses for circuits related to this system before performing the following procedure.

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 A
      Fuel pump operating sound occurs B

    B

    READ VALUE USING GTS (STARTER SIGNAL) Click here

    A

  2. 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

  3. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - FUEL PUMP - BODY GROUND)


    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
      L20-5 (E) - Body ground 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

  4. INSPECT FUEL PUMP


    1. Inspect 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

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


    1. Remove the IG2 relay from the engine room relay block and junction block assembly.

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      5 (IG2 relay) - 1 (C/OPN relay) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Remove the EFI-MAIN relay from the engine room relay block and junction block assembly.

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 (EFI-MAIN relay) - 5 (C/OPN relay) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE C/OPN RELAY

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. 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 value when the ignition switch is turned to the ON and START positions.

      OK
      Switch Position Starter Signal
      ON OFF
      START ON
      Result
      Proceed to
      OK
      NG

    NG

    CHECK STARTER SIGNAL CIRCUIT Click here

    OK

  8. 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