Brand:

Toyota

Model Name:

Yaris NCP90 91 92 93

Manual:

Repair Manual

Section:

1Nz-Fe Engine Control System

Title:

Sfi System

  1. Description

  2. Wiring diagram

  3. Inspection procedure

  4. Perform active test using intelligent tester (control the fuel pump/speed)

  5. Inspect main body ecu (c/opn relay input voltage)

  6. Check harness and connector (main body ecu - integration relay)

  7. Inspect main body ecu (c/opn relay)

  8. Check harness and connector (main body ecu - ecm)

  9. Check harness and connector (c/opn relay - fuel pump - body ground)

  10. Inspect fuel pump

  11. Read value using intelligent tester (starter signal)

  12. Read value using intelligent tester (engine speed)

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 into the STA terminal of the ECM, and NE signal generated by the crankshaft position sensor is also input into the NE+ terminal. Thus, the ECM interprets that the engine is 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 into the ECM, when engine is running, the ECM turns the Tr1 on continuously.

Connect an intelligent tester to the DLC3. Yaris


WIRING DIAGRAM


Connect an intelligent tester to the DLC3. Yaris


INSPECTION PROCEDURE

1.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (CONTROL THE FUEL PUMP/SPEED)

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump/Speed .

  1. Check whether the fuel pump operating sound occurs when perform the Active Test on the tester.

    OK:
    Fuel pump operating sound occurs.


OKnext
Go to step 8
NG
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2.INSPECT MAIN BODY ECU (C/OPN RELAY INPUT VOLTAGE)
  1. Measure the voltage between the terminal of the main body ECU and the body ground when the ignition switch is turned to ON and off.Standard voltage:Tester ConnectionsIgnition Switch ConditionsSpecified Conditions4B-11 - Body groundOFFBelow 1 V4F-4 - Body ground 4B-11 - Body groundON9 to 14 V4F-4 - Body ground Yaris

  2. Measure the voltage between the terminal of the main body ECU and the body ground when the ignition switch is turned to ON and off.

    Standard voltage:
    Tester Connections
    		Ignition Switch Conditions
    		Specified Conditions
    4B-11 - Body ground
    		OFF
    		Below 1 V
    4F-4 - Body ground
    4B-11 - Body ground
    		ON
    		9 to 14 V
    4F-4 - Body ground


OKnext
Go to step 4
NG
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3.CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - INTEGRATION RELAY)
Remove the integration relay from the engine room Relay Block (R/B). Yaris

  1. Remove the integration relay from the engine room Relay Block (R/B).

  1. Disconnect the 4B and 4F main body ECU connectors.

  1. Check the resistance.

    Standard resistance (Check for open):
    Tester Connections
    		Specified Conditions
    1B-4 - 4F-4
    		Below 1 Ω
    1A-4 - 4B-11
    Standard resistance (Check for short):
    Tester Connections
    		Specified Conditions
    4F-4 - Body ground
    		10 kΩ or higher
    4B-11 - Body ground

  1. Reinstall the integration relay.

  1. Reconnect the main body ECU connectors.



NGnext
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
next down
GO TO ECM POWER SOURCE CIRCUIT (Click here)

4.INSPECT MAIN BODY ECU (C/OPN RELAY)
  1. Remove the main body ECU. Yaris

  2. Remove the main body ECU.

  1. Check the C/OPN relay resistance.

    Standard resistance:
    Tester Connections
    		Specified Conditions
    4B-11 - 4A-8
    		10 kΩ or higher
    Below 1 Ω
    (when battery voltage is applied to terminals 4D-1 and 4E-5)
    HINT:
    Relay coil circuit between 4D-1 and 4E-5 is not through IGN fuse.

  1. Reinstall the main body ECU.



NGnext
REPLACE MAIN BODY ECU
OK
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5.CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - ECM)
  1. Disconnect the A21 ECM connector. Yaris

  2. Disconnect the A21 ECM connector.

  1. Disconnect the 4E main body ECU connector.

  1. Check the resistance.

    Standard resistance (Check for open):
    Tester Connections
    		Specified Conditions
    Main body ECU (4E-5) - FC (A21-7)
    		Below 1 Ω
    Standard resistance (Check for short):
    Tester Connections
    		Specified Conditions
    Main body ECU (4E-5) or FC (A21-7) - Body ground
    		10 kΩ or higher

  1. Reconnect the main body ECU connector.

  1. Reconnect the ECM connector.



NGnext
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
next down

6.CHECK HARNESS AND CONNECTOR (C/OPN RELAY - FUEL PUMP - BODY GROUND)
  1. Check the harness and the connectors between the main body ECU and the fuel pump.Disconnect the 4A main body ECU connector.Disconnect the J5 fuel pump connector.Check the resistance.Standard resistance (Check for open):Tester ConnectionsSpecified ConditionsMain body ECU (4A-8) - Fuel pump (J5-4)Below 1 ΩStandard resistance (Check for short):Tester ConnectionsSpecified ConditionsMain body ECU (4A-8) or Fuel pump (J5-4) - Body ground10 kΩ or higher Yaris

  2. Check the harness and the connectors between the main body ECU and the fuel pump.

    1. Disconnect the 4A main body ECU connector.

    2. Disconnect the J5 fuel pump connector.

    3. Check the resistance.

      Standard resistance (Check for open):
      Tester Connections
      		Specified Conditions
      Main body ECU (4A-8) - Fuel pump (J5-4)
      		Below 1 Ω
      Standard resistance (Check for short):
      Tester Connections
      		Specified Conditions
      Main body ECU (4A-8) or Fuel pump (J5-4) - Body ground
      		10 kΩ or higher

  1. Check the harness and the connectors between the fuel pump and the body ground.

    1. Disconnect the J5 fuel pump connector.

    2. Check the resistance.

      Standard resistance (Check for open):
      Tester Connections
      		Specified Conditions
      Fuel pump (J5-5) - Body ground
      		Below 1 Ω

  1. Reconnect the main body ECU connector.

  1. Reconnect the fuel pump connector.



NGnext
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
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7.INSPECT FUEL PUMP
  1. Inspect fuel pump resistance.Measure the resistance between the terminals.Standard resistance:0.2 to 3.0 Ω at 20°C (68°F) Yaris

  2. Inspect fuel pump resistance.

    1. Measure the resistance between the terminals.

      Standard resistance:
      0.2 to 3.0 Ω at 20°C (68°F)

  1. Inspect fuel pump operation.

    1. Apply the battery voltage to both the terminals. Check that the pump operates.

      NOTICE:
      1. These tests must be done quickly (within 10 seconds) to prevent the coil from burning out.
      2. Keep the fuel pump as far away from the battery as possible.
      3. Always switch at the battery side.


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REPLACE FUEL PUMP (Click here)
OK
next down
REPLACE ECM (Click here)

8.READ VALUE USING INTELLIGENT TESTER (STARTER SIGNAL)

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Select the following menu items: Powertrain / Engine and ECT / Data List / Starter Signal.

  1. Check the result when the ignition switch is turned to ON and START.

    OK:
    Conditions
    		Starter Signal
    Ignition switch to ON
    		OFF
    Engine start
    		ON


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REPAIR OR REPLACE STARTING SYSTEM
OK
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9.READ VALUE USING INTELLIGENT TESTER (ENGINE SPEED)

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Select the following menu items: Powertrain / Engine and ECT / Data List / Engine Speed.

  1. Read the values displayed on the tester while cranking.

    Standard:
    Values are displayed continuously.


NGnext
REPAIR OR REPLACE CRANKSHAFT POSITION SENSOR CIRCUIT
OK
next down
REPLACE ECM (Click here)