SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

When the engine is cranked, the ST (Starter) relay drive signal output from the STAR terminal of the ECM 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 Tr1 in the ECM internal circuit ON. The current flows to the C/OPN (Circuit Opening) relay by turning the Tr1 ON. Then, the fuel pump operates.

While the NE signal is input to the ECM with the engine running, the ECM turns the Tr1 on continuously.

WIRING DIAGRAM

A0117YEE03

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 (CONTROL THE FUEL PUMP/SPD)


    1. Connect an 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 operating sound occurs when performing the Active Test on the tester.

      Result
      Result Proceed to
      Fuel pump operating sound does not occur A
      Fuel pump operating sound occurs B

    B

    READ VALUE USING INTELLIGENT TESTER (STARTER SIGNAL) Click here

    A

  2. INSPECT INTEGRATION RELAY (C/OPN RELAY)

    A01171RE01
    Text in Illustration
    *1

    Front view of wire harness connector:

    (to Integration Relay)
    *2

    Front view of wire harness connector:

    (to Integration Relay)

    1. Remove the integration 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
      Tester Connection Condition Specified Condition
      1B-4 - 1D-8 When battery voltage absent 10 kΩ or higher
      When battery voltage applied to terminals 1B-9 and 1E-4 Below 1 Ω

    4. Reinstall the integration relay.

    5. Reconnect the ECM connector.


    NG

    REPLACE INTEGRATION NO.1 RELAY Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM)

    A0119KQE01
    Text in Illustration
    *1

    Front view of wire harness connector:

    (to Integration Relay)
    *2

    Front view of wire harness connector:

    (to ECM)

    1. Remove the integration 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
      1B-9 - A18-19 (FC) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      1B-9 or A18-19 (FC) - Body ground Always 10 kΩ or higher

    4. Reinstall the integration relay.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - FUEL PUMP - BODY GROUND)

    A0117MGE01
    Text in Illustration
    *1

    Front view of wire harness connector:

    (to Integration Relay)
    *2

    Front view of wire harness connector:

    (to ECM)

    1. Remove the integration relay from the engine room relay block.

    2. Disconnect the fuel pump connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      1D-8 - L1-4 Always Below 1 Ω
      L1-5 - Body ground Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      1D-8 or L1-4 - Body ground Always 10 kΩ or higher

    4. Install integration relay from the engine room relay block.

    5. Reconnect the fuel pump connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. INSPECT FUEL PUMP

    A0116XIE02
    Text in Illustration
    *1

    Component without harness connected:

    (Fuel Pump)

    1. Inspect fuel pump resistance.


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

        Standard Resistance
        Tester Connection Condition Specified Condition
        4 - 5 20°C (68°F) 0.2 to 3.0 Ω

    2. Inspect fuel pump operation.


      1. Apply battery voltage to the fuel pump terminals.

      2. Check that the fuel pump operates.

        CAUTION:


        • This test must be done quickly (within 10 seconds) to prevent the coil from burning out.

        • Keep the fuel pump as far away from the battery as possible.

        • Always switch at the battery side.


    NG

    REPLACE FUEL PUMP Click here

    OK

    REPLACE ECM Click here

  6. READ VALUE USING INTELLIGENT TESTER (STARTER SIGNAL)


    1. Connect an 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 / Data List / Starter Signal.

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

      OK
      Condition Starter Signal
      Ignition switch ON OFF
      Engine Start ON

    NG

    CHECK STARTING SYSTEM Click here

    OK

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