SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

• When the engine is cranked, the ST NO.1 relay drive signal output from the ignition switch assembly 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 NO.1 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.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

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 > 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 (w/o Entry and Start System) A Fuel pump operating sound does not occur (w/ Entry and Start System) B Fuel pump operating sound occurs C

   
   

   B

   GO TO STEP 3 Click here

   C

   READ VALUE USING GTS (STARTER SIGNAL) Click here

   A

2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF C/OPN NO. 1 RELAY)

   
   
   1. 

      *a	Front view of wire harness connector (to Instrument Panel Junction Block Assembly)

      Disconnect the instrument panel junction block assembly connector.

   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 2G-1 - Body ground Ignition switch ON 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) Click here

   OK

3. INSPECT C/OPN NO. 1 RELAY

   
   

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

      Click here

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

   OK

4. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - ECM)

   
   

   1. Disconnect the instrument panel junction block assembly 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 - G45-5 (FC) Always Below 1 Ω 2P-8 or G45-5 (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 (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - FUEL PUMP)

   
   

   1. Disconnect the instrument panel junction block assembly connector.

   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 2K-5 - O6-4 Always Below 1 Ω 2K-5 or O6-4 - 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 O6-5 - 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 fuel pump.

      
      

      • For long wheelbase

        Click here

      • for short wheelbase

        Click here

      Tech Tips

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

      Click here

      Result
      Result Proceed to OK A NG (for long wheelbase) B NG (for short wheelbase) C

   
   

   A

   GO TO ECM POWER SOURCE CIRCUIT Click here

   B

   REPLACE FUEL PUMP Click here

   C

   REPLACE FUEL PUMP Click here

8. CHECK HARNESS AND CONNECTOR (IGNITION SWITCH ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

   
   

   1. Disconnect the ignition switch assembly connector.

   2. Disconnect the instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition G1-3 (IG2) - 2G-1 Always Below 1 Ω G1-3 (IG2) or 2G-1 - 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. 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 > 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

10. 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 > 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