SFI SYSTEM Fuel Pump Control Circuit

DTC Code DTC Name
Fuel Pump Control Circuit

DESCRIPTION

When the engine is cranked, the ST NO. 1 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 in the ECM internal circuit on. The current flows to the C/OPN relay by turning the transistor on. Then, the fuel pump operates.

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

WIRING DIAGRAM

A300195E01

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 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 (C/OPN RELAY - ECM)

    1. Remove the C/OPN 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

      2 (C/OPN relay) - A50-21 (FC)

      Always

      Below 1 Ω

      2 (C/OPN relay) or A50-21 (FC) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

    1. Remove the C/OPN 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

      3 (C/OPN relay) - L20-4 (B)

      Always

      Below 1 Ω

      L20-5 (E) - Body ground

      Always

      Below 1 Ω

      3 (C/OPN relay) or L20-4 (B) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT FUEL PUMP

    1. Inspect fuel pump.

      Click here

      Tip:

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

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE FUEL PUMP

    Click hereClick hereClick here

    OK

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

    1. Remove the IG2 relay from the engine room relay block and junction block assembly.

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

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      5 (IG2 relay) - 1 (C/OPN relay)

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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

    1. Remove the EFI-MAIN relay from the engine room relay block and junction block assembly.

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

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      3 (EFI-MAIN relay) - 5 (C/OPN relay)

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE C/OPN RELAY

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. 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 value when the ignition switch is turned to the ON and START positions.

      OK

      Switch Position

      Starter Signal

      ON

      OFF

      START

      ON

    Result

    Proceed to

    OK

    NG
    NG

    CHECK STARTER SIGNAL CIRCUIT

    Click hereClick here

    OK

  8. 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 hereClick hereClick here

    NG

    CHECK CRANKSHAFT POSITION SENSOR CIRCUIT

    Click hereClick here