SFI SYSTEM Fuel Pump Control Circuit

DESCRIPTION

• When the engine is cranked, the ST NO.1 relay drive signal output from the certification ECU (smart key ECU assembly)*1 or ignition or starter switch 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 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/ Entry and Start System

  *2: w/o Entry and Start System

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 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. 

      *1	No.1 Engine Room Relay Block
      *2	C/OPN Relay Holder

      Remove the C/OPN relay from the No.1 engine room relay block.

   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 holder) - Body ground Ignition switch ON 11 to 14 V

      Result
      Proceed to OK NG

   
   

   NG

   CHECK HARNESS AND CONNECTOR (C/OPN RELAY - NO.1 INTEGRATION 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 No.1 engine room relay block.

   2. Disconnect the A38 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 holder) - A38-41 (FC) Always Below 1 Ω 2 (C/OPN relay holder) or A38-41 (FC) - Body ground and other terminals Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (C/OPN RELAY - ECM)

   OK

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

   
   

   1. Remove the C/OPN relay from the No.1 engine room relay block.

   2. Disconnect the Fuel Suction Tube with Pump and Gauge Assembly 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 holder) - M14-4 (B) Always Below 1 Ω 3 (C/OPN relay holder) or M14-4 (B) - Body ground and other terminals Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (C/OPN RELAY - FUEL PUMP)

   OK

6. CHECK HARNESS AND CONNECTOR (FUEL PUMP - BODY GROUND)

   
   

   1. Disconnect the M14 Fuel Suction Tube with Pump and Gauge Assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition M14-5 (E) - Body ground Always Below 1 Ω

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (FUEL PUMP - BODY GROUND)

   OK

7. INSPECT FUEL PUMP

   
   

   1. Inspect fuel pump.

      Click here

      Tech Tips

      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 NO.1 RELAY)

   
   

   1. Remove the C/OPN relay and EFI-MAIN NO.1 relay from the No.1 engine room relay block .

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

      Standard Resistance
      Tester Connection Condition Specified Condition 5 (C/OPN relay holder) - 3 (EFI-MAIN NO.1 relay holder) Always Below 1 Ω 5 (C/OPN relay holder) or 3 (EFI-MAIN NO.1 relay holder) - Body ground Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   CHECK ECM POWER SOURCE CIRCUIT Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (C/OPN RELAY - EFI-MAIN NO.1 RELAY)

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

   
   

   1. Remove the C/OPN relay from the No.1 engine room relay block.

   2. Disconnect the 1A integration relay connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition 1 (C/OPN relay holder) - 1A-9 Always Below 1 Ω 1 (C/OPN relay holder) or 1A-9 - Body ground and other terminals Always 10 kΩ or higher

      Result
      Proceed to OK NG

   
   

   OK

   CHECK ECM POWER SOURCE CIRCUIT Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (C/OPN RELAY - NO.1 INTEGRATION RELAY)

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