SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

In the diagram below, when the engine is cranked, current flows from terminal ST1 (STR) of the engine switch 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 keeps operating.

A01CE92E03

WIRING DIAGRAM

A01CC6JE03

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 engine switch on (IG).

    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 using the tester.

      OK
      Fuel pump operating sound occurs.

    NG

    INSPECT RELAY (C/OPN RELAY) Click here

    OK

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

  2. INSPECT RELAY (C/OPN RELAY)


    1. A01CC90

      Remove the C/OPN relay from the engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 No battery voltage is applied across terminals 1 and 2 10 kΩ or higher
      3 - 5 Battery voltage applied across terminals 1 and 2 Below 1 Ω

    3. Reinstall the C/OPN relay.


    NG

    REPLACE RELAY (C/OPN RELAY)

    OK

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


    1. Remove the C/OPN relay from the engine room relay block.

    2. Remove the IG2 relay from the engine room relay block.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      1 (C/OPN relay terminal) - 3 (IG2 relay terminal) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      1 (C/OPN relay terminal) or 3 (IG2 relay terminal) - Body ground Always 10 kΩ or higher

    4. Reinstall the IG2 relay.

    5. Reinstall the C/OPN relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (C/OPN RELAY - IG2 RELAY)

    OK

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


    1. Remove the C/OPN relay from the engine room relay block.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      2 (C/OPN relay terminal) - A8-7 (FC) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      2 (C/OPN relay terminal) or A8-7 (FC) - Body ground Always 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reinstall the C/OPN relay.


    NG

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

    OK

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


    1. Remove the C/OPN relay from the engine room relay block.

    2. Remove the EFI MAIN relay from the engine room relay block.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      5 (C/OPN relay terminal) - 3 (EFI MAIN relay terminal) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      5 (C/OPN relay terminal) or 3 (EFI MAIN relay terminal) - Body ground Always 10 kΩ or higher

    4. Reinstall the EFI MAIN relay.

    5. Reinstall the C/OPN relay.


    NG

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

    OK

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


    1. Disconnect the fuel pump connector.

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

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      3 (C/OPN relay terminal) - N19-4 Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      3 (C/OPN relay terminal) or N19-4 - Body ground Always 10 kΩ or higher

    4. Reconnect the fuel pump connector.

    5. Reinstall the C/OPN relay.


    NG

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

    OK

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


    1. 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
      N19-5 - Body ground Always Below 1 Ω

    3. Reconnect the fuel pump connector.


    NG

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

    OK

  8. INSPECT FUEL PUMP ASSEMBLY


    1. Inspect the fuel pump assembly Click here.


    NG

    REPLACE FUEL PUMP ASSEMBLY Click here

    OK

  9. 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