SFI SYSTEM > Fuel Pump Control Circuit

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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


A187734E01


INSPECTION PROCEDURE

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

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

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Fuel Pump/Speed.

  1. 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
Go to step 6
A


2.INSPECT INTEGRATION RELAY (C/OPEN RELAY)
A201355E01

  1. Remove the integration relay.

  1. Disconnect the ECM connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1B-4 - 1D-8
    		Battery voltage not applied
    		10 kΩ or higher
    Battery voltage applied to terminals 1B-9 and 1E-4
    		Below 1 Ω

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Integration Relay)
    *2
    		Front view of wire harness connector
    (to Integration Relay)

  1. Reinstall the integration relay.

  1. Reconnect the ECM connector.



NG
REPLACE INTEGRATION NO.1 RELAY (Click here)
OK


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

  1. Remove the integration relay.

  1. Disconnect the ECM connector.

  1. 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

  1. Reinstall the integration relay.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


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

  1. Remove the integration relay.

  1. Disconnect the fuel pump connector.

  1. 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

  1. Install integration relay.

  1. Reconnect the fuel pump connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


5.INSPECT FUEL PUMP
A200918E02

  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

      Text in Illustration 
      *1
      		Component without harness connected
      (Fuel Pump)

  1. Inspect fuel pump operation.

    1. Apply battery voltage to the fuel pump terminals.

    2. Check that the fuel pump operates.

      CAUTION:
      1. This test 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.



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.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / Starter Signal.

  1. 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



B
CHECK CRANKING HOLDING FUNCTION CIRCUIT (Click here)

C
CHECK STARTER SIGNAL CIRCUIT (Click here)
A

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