SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

When the engine is cranked, the ST (Starter) 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 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

A005J3VE02

CAUTION / NOTICE / HINT

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 NO. 1 INTEGRATION RELAY (C/OPEN RELAY)


    1. Inspect the No. 1 integration relay Click here.


    NG

    REPLACE NO. 1 INTEGRATION RELAY Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - ECM)


    1. Remove the No. 1 integration relay.

    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
      1E-11 - A58-21 (FC) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      1E-11 or A58-21 (FC) - Body ground Always 10 kΩ or higher

    4. Reinstall the No. 1 integration relay.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY - FUEL PUMP - BODY GROUND)


    1. Remove the No. 1 integration relay.

    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
      1E-5 - K17-4 Always Below 1 Ω
      K17-5 - Body ground Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      1E-5 or K17-4 - Body ground Always 10 kΩ or higher

    4. Install No. 1 integration relay.

    5. Reconnect the fuel pump connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. INSPECT FUEL PUMP


    1. Inspect the fuel pump Click here.


    OK

    REPLACE ECM Click here

    NG

    REPLACE FUEL PUMP 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
      Result
      Result Proceed to
      OK A

      NG

      (w/ Entry and Start System)

      		 B

      NG

      (w/o Entry and Start System)

      		 C

    A

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

    B

    CHECK CRANKING HOLDING FUNCTION CIRCUIT Click here

    C

    CHECK STARTER SIGNAL CIRCUIT Click here