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SFI SYSTEM Fuel Pump Control Circuit

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DTC Code DTC Name
  Fuel Pump Control Circuit
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DESCRIPTION

When the engine is cranked, an STA signal is sent to the ECM from ignition switch*1 or certification ECU (smart key ECU assembly)*2. When the STA and NE signals are received by the ECM, Tr1 inside the ECM turns on and current flows through the coil of the C/OPN NO.1 relay. As a result, the relay switches on and the fuel pump operates with power from the FUEL PMP/AIR PMP HTR relay. While the NE signal is being sent (while the engine is running), the fuel pump continues to operate since Tr1 in the ECM continues to stay on (the C/OPN NO.1 relay is on). The speed of the fuel pump is regulated at two speeds (high and low) according to the state of the engine (cranking, light load or heavy load). When Tr2 inside the ECM is off, the fuel pump operates at high speed. When Tr2 turns on during idling or light loads, current flows to the fuel pump through the fuel pump resistor and the fuel pump operates at low speed.

*1: w/o Entry and Start System

*2: w/ Entry and Start System

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WIRING DIAGRAM

Refer to DTC P0230.

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CAUTION / NOTICE / HINT

Note:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

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PROCEDURE


  1. Click here

    PERFORM ACTIVE TEST USING GTS (OPERATE C/OPN NO.1 RELAY)


    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.


      1. Powertrain > Engine > Active Test
        Tester Display
        Control the Fuel Pump / Speed




    5. Check the relay operation while operating it using the GTS.

      Standard
      Operating noise can be heard from the relay.
      Result
      Proceed to
      OK
      NG

  2. Click here

    INSPECT RELAY (FUEL PMP/AIR PMP HTR)


    1. Inspect the relay (FUEL PMP/AIR PMP HTR).

      Click here

      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPLACE RELAY (FUEL PMP/AIR PMP HTR)

  3. *1 Engine Room Relay Block Assembly *2 FUEL PMP/AIR PMP HTR
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    INSPECT TERMINAL VOLTAGE (FUEL PMP/AIR PMP HTR RELAY TERMINAL)


    1. Remove the FUEL PMP/AIR PMP HTR relay from the engine room relay block assembly.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      FUEL PMP/AIR PMP HTR relay terminal 2 - Body ground Cranking 11 to 14 V
      FUEL PMP/AIR PMP HTR relay terminal 3 - Body ground Cranking 11 to 14 V
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR (C/OPN NO.1 RELAY - FUEL PMP/AIR PMP HTR RELAY, EFI-MAIN NO.1 RELAY)

  4. Click here

    INSPECT FUEL PUMP RESISTOR

    Inspect fuel pump resistor.

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    Result
    Result Proceed to
    OK A
    NG B

  5. Click here

    INSPECT FUEL PUMP


    1. Inspect the fuel pump.

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      Tip:

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

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      Result
      Proceed to
      OK
      NG

  6. Click here

    CHECK HARNESS AND CONNECTOR (FUEL PMP/AIR PMP HTR RELAY - FUEL PUMP RESISTOR, FUEL PUMP, ECM)


    1. Remove the FUEL PMP/AIR PMP HTR relay from the engine room relay block assembly.

    2. Disconnect the fuel pump resistor connector.

    3. Disconnect the fuel pump connector.

    4. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      FUEL PMP/AIR PMP HTR relay terminal 5 - A53-1 Always Below 1 Ω
      A53-2 - O6-4 Always Below 1 Ω
      FUEL PMP/AIR PMP HTR relay terminal 4 - O6-4 Always Below 1 Ω
      O6-5 - Body ground Always Below 1 Ω
      FUEL PMP/AIR PMP HTR relay terminal 1 - G87-4 (FPR) Always Below 1 Ω
      FUEL PMP/AIR PMP HTR relay terminal 5 or A53-1 - Body ground Always 10 kΩ or higher
      A53-2 or O6-4 - Body ground Always 10 kΩ or higher
      FUEL PMP/AIR PMP HTR relay terminal 4 or O6-4 - Body ground Always 10 kΩ or higher
      FUEL PMP/AIR PMP HTR relay terminal 1 or G87-4 (FPR) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OK

      CHECK CHECK FOR INTERMITTENT PROBLEMSClick here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

  7. Click here

    CHECK ECM POWER SOURCE CIRCUIT


    1. Inspect the ECM power source circuit.

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      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE ECM POWER SOURCE CIRCUIT

  8. Click here

    INSPECT RELAY (C/OPN NO.1)


    1. Inspect the relay (C/OPN NO.1).

      Click here

      Result
      Proceed to
      OK
      NG

  9. Click here

    CHECK HARNESS AND CONNECTOR (C/OPN NO.1 RELAY - ECM)


    1. Disconnect the instrument panel junction block connector.

    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
      2P-8 - G87-5 (FC) Always Below 1 Ω
      2P-8 or G87-5 (FC) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OK

      REPLACE ECMClick here

    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR