SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

When the engine is cranked, the ST (Starter) 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 Tr1 in the ECM internal circuit ON. The current flows to the C/OPN (Circuit Opening) relay by turning the Tr1 ON. Then, the fuel pump operates.

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

WIRING DIAGRAM

A01VGL2E01

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


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


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

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

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

      Result
      Result Proceed to
      Fuel pump operating sound does not occur A
      Fuel pump operating sound occurs B

    B

    READ VALUE USING INTELLIGENT TESTER (STARTER SIGNAL) Click here

    A

  2. INSPECT NO. 1 INTEGRATION RELAY (C/OPEN RELAY)


    1. Inspect the No. 1 integration relay Click here.


    NG

    REPLACE NO. 1 INTEGRATION RELAY Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - ECM)


    1. Remove the No. 1 integration relay from 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
      1E-11 - A58-21 (FC) Always Below 1 Ω
      1E-11 or A58-21 (FC) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - FUEL PUMP - BODY GROUND)


    1. Remove the No. 1 integration relay from engine room relay block.

    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
      1E-5 - K17-4 Always Below 1 Ω
      K17-5 - Body ground Always Below 1 Ω
      1E-5 or K17-4 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. INSPECT FUEL PUMP


    1. Inspect the fuel pump Click here.

      Tech Tips

      Perform "Inspection After Repairs" after replacing the fuel pump Click here.


    OK

    REPLACE ECM Click here

    NG

    REPLACE FUEL PUMP Click here

  6. READ VALUE USING INTELLIGENT TESTER (STARTER SIGNAL)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Starter Signal.

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

      OK
      Condition Starter Signal
      Ignition switch ON Close (OFF)
      Engine Start Open (ON)
      Result
      Result Proceed to
      OK A

      NG

      (w/ Entry and Start System)

      		 B

      NG

      (w/o Entry and Start System)

      		 C

    B

    CHECK CRANKING HOLDING FUNCTION CIRCUIT Click here

    C

    CHECK STARTER SIGNAL CIRCUIT Click here

    A

  7. READ VALUE USING INTELLIGENT TESTER (ENGINE SPEED)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Engine Speed.

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

      OK
      Values are displayed continuously.

    OK

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

    NG

    CHECK CRANKSHAFT POSITION SENSOR CIRCUIT Click here