SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

When the engine is cranked, the ST (Starter) relay drive signal output from the ignition switch assembly*1 or certification ECU (smart key ECU assembly)*2 is input to the STA terminal of the ECM, and the 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 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 to the ECM with the engine running, the ECM turns Tr1 on continuously.


WIRING DIAGRAM

B000JKUE01

INSPECTION PROCEDURE

Note

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

    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 (NO. 1 INTEGRATION RELAY - ECM)


    1. Remove the No. 1 integration 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
      1E-1 - A25-21 (FC) Always Below 1 Ω
      1E-1 or A25-21 (FC) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Remove the No. 1 integration 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
      1C-6 - N11-4 (B) Always Below 1 Ω
      N11-5 (E)- Body ground Always Below 1 Ω
      1C-6 or N11-4 (B) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT FUEL PUMP


    1. Inspect the fuel pump Click here for TMC made, Click here for TMMK made).

      Tech Tips

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

      Result
      Result Proceed to
      OK A
      NG (for TMC made) B
      NG (for TMMK made) C

    B

    REPLACE FUEL PUMP Click here

    C

    REPLACE FUEL PUMP Click here

    A

  5. CHECK HARNESS AND CONNECTOR (BATTERY - NO. 1 INTEGRATION RELAY)


    1. Remove the No. 1 integration 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
      1D-1 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE NO. 1 INTEGRATION RELAY Click here

  6. 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.

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

      OK
      Ignition Switch Position Starter Signal
      ON OFF
      START ON

    NG

    CHECK STARTER SIGNAL CIRCUIT Click here

    OK

  7. 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.

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

      OK
      Values are displayed continuously.

    NG

    CHECK CRANKSHAFT POSITION SENSOR CIRCUIT Click here

    OK

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