SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

When the engine is cranked, the starter (ST) relay drive signal output from the ignition 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 input into the NE+ terminal. The ECM interprets that the engine is being 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 Smart Entry and Start System.

*2: w/ Smart Entry and Start System.

WIRING DIAGRAM

A00286IE03

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 sounds 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. INSPECT CIRCUIT OPENING RELAY (C/OPN RELAY)


    1. Inspect the C/OPN relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE RELAY (C/OPN RELAY)

    OK

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


    1. Disconnect the ECM connector.

    2. Remove the C/OPN relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A43-21 (FC) - 2 (C/OPN relay) Always Below 1 Ω
      A43-21 (FC) or 2 (C/OPN relay) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - C/OPN RELAY)


    1. Disconnect the semiconductor pwr integration ECU connector.

    2. Remove the C/OPN relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      1G-4 - 1 (C/OPN relay) Always Below 1 Ω
      1F-1 - 5 (C/OPN relay) Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Remove the C/OPN relay from the No. 1 engine room relay block and No. 1 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) - M9-4 Always Below 1 Ω
      M9-5 - Body ground Always Below 1 Ω
      3 (C/OPN relay) or M9-4 - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. 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

  7. INSPECT SEMICONDUCTOR PWR INTEGRATION ECU


    1. Inspect the semiconductor pwr integration ECU.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

    CHECK ECM POWER SOURCE CIRCUIT Click here

    NG

    REPLACE SEMICONDUCTOR PWR INTEGRATION ECU Click here

  8. 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
      Cranking ON
      Result
      Proceed to
      OK
      NG

    NG

    CHECK STARTER SIGNAL CIRCUIT Click here

    OK

  9. 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