SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

When the engine is cranked, current flows from terminal ST1 (STR) of the ignition switch (power management control ECU) to the starter relay coil and current also flows to terminal STA of the ECM (STA signal).

When the STA signal and NE signal are input to the ECM, Tr is turned on, current flows to the coil of the circuit opening relay, the relay switches on, power is supplied to the fuel pump and the fuel pump operates.

While the NE signal is generated (engine running), the ECM keeps Tr on (circuit opening relay on) and the fuel pump also keeps operating.

A00DQOXE02

WIRING DIAGRAM

A00DSMSE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (OPERATE C/OPN RELAY)


    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 operation sound occurs when performing the Active Test on the tester.

      OK
      Fuel pump operating sound occurs.

    NG

    INSPECT INSTRUMENT PANEL JUNCTION BLOCK (C/OPN RELAY) Click here

    OK

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

  2. INSPECT INSTRUMENT PANEL JUNCTION BLOCK (C/OPN RELAY)


    1. A00DSSZE38
      Text in Illustration
      *1

      Component without harness connected

      (Instrument Panel Junction Block)

      Disconnect the instrument panel junction block connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      DA-8 - DB-11 Battery voltage not applied to terminals DB-10 and DF-4 10 kΩ or higher
      Battery voltage applied to terminals DB-10 and DF-4 Below 1 Ω

    3. Reconnect the instrument panel junction block connector.


    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK (C/OPN RELAY)

    OK

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


    1. A00DU2NE01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Instrument Panel Junction Block)
      *2 Instrument Panel Junction Block
      *3

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

    2. Disconnect the instrument panel junction block connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      DB-10 - A40-19 (FC) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      DB-10 or A40-19 (FC) - Body ground Always 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reconnect the instrument panel junction block connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (C/OPN RELAY - ECM)

    OK

  4. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - INTEGRATION RELAY [EFI MAIN RELAY, IG2 RELAY])


    1. A00DSOUE01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Instrument Panel Junction Block)
      *2 Instrument Panel Junction Block
      *3 Engine Room No. 1 Relay Block
      *4

      Front view of wire harness connector

      (to Integration Relay)

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

    2. Disconnect the integration relay connector.

    3. Disconnect the instrument panel junction block connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      DB-11 - 1B-4 Always Below 1 Ω
      DF-4 - 1A-4 Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      DB-11 or 1B-4 - Body ground Always 10 kΩ or higher
      DF-4 or 1A-4 - Body ground Always 10 kΩ or higher

    5. Reconnect the instrument panel junction block connector.

    6. Reconnect the integration relay connector.

    7. Reinstall the integration relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (C/OPN RELAY - INTEGRATION RELAY [EFI MAIN RELAY])

    OK

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


    1. A00DTRLE04
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Instrument Panel Junction Block)
      *2 Instrument Panel Junction Block
      *3

      Front view of wire harness connector

      (to Fuel Pump)

      Disconnect the fuel pump connector.

    2. Disconnect the instrument panel junction block connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      DA-8 - G24-4 Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      DA-8 or G24-4 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (C/OPN RELAY - FUEL PUMP)

    OK

  6. CHECK HARNESS AND CONNECTOR (FUEL PUMP - BODY GROUND)


    1. A00DSEEE12
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Fuel Pump)

      Disconnect the fuel pump connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G24-5 - Body ground Always Below 1 Ω

    3. Reconnect the fuel pump connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FUEL PUMP - BODY GROUND)

    OK

  7. INSPECT FUEL PUMP


    1. Inspect the fuel pump Click here.


    NG

    REPLACE FUEL PUMP Click here

    OK

  8. CHECK ECM POWER SOURCE CIRCUIT


    1. Check the ECM power source circuit Click here.


    NG

    REPAIR OR REPLACE ECM POWER SOURCE CIRCUIT

    OK

    REPLACE ECM Click here