SFI SYSTEM Fuel Pump Control Circuit

DTC Code DTC Name
Fuel Pump Control Circuit

DESCRIPTION

When the engine is cranked, the starter (ST NO. 1) relay drive signal output from the ignition or starter switch assembly*1 or certification ECU (smart key ECU assembly)*2 is input into the STA terminal of the ECM, and the NE signal generated by the crankshaft position sensor is also input into the NE+ terminal. The ECM interprets that the engine is cranked, and turns transistor Tr1 in the ECM internal circuit on. Current flows to the C/OPN (Circuit Opening) relay by turning Tr1 on. Then, the fuel pump operates.

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

*1: w/o entry and start system.

*2: w/ entry and start system.

WIRING DIAGRAM

A297436E03

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 TERMINAL VOLTAGE (POWER SOURCE OF C/OPN RELAY)

    1. A296677C01

      *1

      Engine Room Relay Block and Junction Block Assembly

      *2

      C/OPN Relay

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

    2. Turn the ignition switch to ON.

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      1 (C/OPN relay) - Body ground

      Ignition switch ON

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    CHECK HARNESS AND CONNECTOR (C/OPN RELAY - IG2 RELAY)Click here

    OK

  3. INSPECT C/OPN RELAY

    1. Inspect the C/OPN relay.

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE C/OPN RELAY

    OK

  4. 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

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

    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

      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

  6. 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

      L20-5 (E) - Body ground

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. INSPECT FUEL PUMP

    1. Inspect the 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 here

    OK

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

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

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

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

      Always

      Below 1 Ω

      5 (C/OPN relay) or 3 (EFI-MAIN relay) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    OK

    GO TO ECM POWER SOURCE CIRCUIT

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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

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

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

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

      Always

      Below 1 Ω

      1 (C/OPN relay) or 5 (IG2 relay) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    OK

    GO TO ECM POWER SOURCE CIRCUIT

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  10. 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 result when the ignition switch is ON and the engine starts.

      OK

      Condition

      Starter Signal

      Ignition switch ON

      OFF

      Engine Started

      ON

    Result

    Proceed to

    OK

    NG
    NG

    CHECK STARTER SIGNAL CIRCUIT

    Click here

    OK

  11. 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 here

    NG

    CHECK CRANKSHAFT POSITION SENSOR CIRCUIT

    Click here