Lexus IS250 · Service Manual ENGINE

Fuel Pump Control Circuit

Circuit diagnosis

DESCRIPTION

Refer to DTC P0230 (Click here).

WIRING DIAGRAM

Refer to DTC P0230 (Click here).

INSPECTION PROCEDURE


1. CHECK FUEL PUMP (FUEL PUMP OPERATION)

  1. Check if there is pressure in the fuel inlet hose.

    HINT:
    If there is fuel pressure, you will hear the sound of fuel flowing.



 OK
Go to step 12
NG


2. PERFORM ACTIVE TEST BY INTELLIGENT TESTER (OPERATE CIRCUIT OPENING RELAY)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG) and turn the intelligent tester ON.

  1. Enter the following menus: Power train / Engine / Active Test / Control the Fuel Pump / Speed.

  1. Check the operation of the relay while operating it using the intelligent tester.

    OK:
    Operating noise can be heard from the relay.



 OK
Go to step 8
NG


3. INSPECT ECM POWER SOURCE CIRCUIT


NG
REPAIR OR REPLACE POWER SOURCE CIRCUIT
OK


4. INSPECT FUSE (F/PMP FUSE)

  1. A108303E06
    Remove the F/PMP fuse from the engine room J/B and R/B No. 2.

  1. Measure the resistance of the F/PMP fuse.

    Standard resistance:
    Below 1 Ω



 NG
REPLACE FUSE
OK


5. INSPECT INTEGRATION RELAY (EFI NO. 2 RELAY)

  1. A107685E07
    Remove the integration relay from the engine room J/B and R/B No. 2.

  1. Measure the resistance of the EFI No. 2 relay.

    Standard resistance:
    Tester Connection
    		 Specified Condition
    2B-4 - 2C-1
    		 10 kΩ or higher
    2B-4 - 2C-1
    		 Below 1 Ω
    (when battery voltage applied to terminals 2B-3 and 2B-2)



NG
REPLACE INTEGRATION RELAY
OK


6. INSPECT INTEGRATION RELAY (C/OPN RELAY)

  1. A107685E07
    Remove the integration relay from the engine room J/B and R/B No. 2.

  1. Measure the resistance of the C/OPN relay.

    Standard resistance:
    Tester Connection
    		 Specified Condition
    2B-6 - 2B-8
    		 10 kΩ or higher
    2B-6 - 2B-8
    		 Below 1 Ω
    (when battery voltage applied to terminals 2B-6 and 2B-7)



NG
REPLACE INTEGRATION RELAY
OK


7. INSPECT ECM (FC VOLTAGE)

  1. A124678E10
    Turn the engine switch on (IG).

  1. Measure the voltage of the A5 and E4 ECM connectors.

    Standard voltage:
    Tester Connection
    		 Specified Condition
    FC (A5-14) - E1 (E4-7)
    		 9 to 14 V



OK
REPLACE ECM
NG

CHECK AND REPAIR HARNESS AND CONNECTOR (ECM - CIRCUIT OPENING RELAY)

8. INSPECT F/PMP RELAY

  1. A095468
    Remove the F/PMP relay from the engine room J/B and R/B No. 2.

  1. Measure the resistance of the F/PMP relay.

    Standard resistance:
    Tester Connection
    		 Specified Condition
    3 - 4
    		 10 kΩ or higher
    3 - 4
    		 Below 1 Ω
    (when battery voltage applied to terminals 1 and 2)



NG
REPLACE F/PMP RELAY
OK


9. INSPECT FUEL PUMP

  1. A074356E16
    Inspect fuel pump resistance.

    1. Measure the resistance between terminals 4 and 5.

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

  1. Inspect fuel pump operation.

    1. Apply 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 fuel pump as far away from the battery as possible.
      3. Always switch at the battery side.



 NG
REPLACE FUEL PUMP
OK


10. CHECK HARNESS AND CONNECTOR (FUEL PUMP - F/PMP RELAY)

  1. A108343E09
    Check the harness and the connectors between the fuel pump and the F/PMP relay.

    1. Disconnect the fuel pump connector.

    2. Remove the F/PMP relay from the engine room J/B and R/B No. 2.

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance (Check for open):
      Tester Connection
      		 Specified Condition
      Fuel pump (Q14-4) - F/PMP relay (4)
      		 Below 1 Ω

      Standard resistance (Check for short):
      Tester Connection
      		 Specified Condition
      Fuel pump (Q14-4) or F/PMP (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 fuel pump connector.

    2. Measure the resistance of the wire harness side connector and the body ground.

      Standard resistance (Check for open):
      Tester Connection
      		 Specified Condition
      Fuel pump (Q14-5) - Body ground
      		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


11. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - F/PMP RELAY)

  1. A109880E03
    Remove the integration relay from the engine room J/B and R/B No. 2.

  1. Remove the F/PMP relay from the engine room J/B and R/B No. 2.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance (Check for open):
    Tester Connection
    		 Specified Condition
    Integration relay (2B-8) - F/PMP relay (1)
    		 Below 1 Ω
    Integration relay (2B-8) - F/PMP relay (3)
    		 Below 1 Ω

    Standard resistance (Check for short):
    Tester Connection
    		 Specified Condition
    Circuit opening relay (2B-8) or F/PMP relay (1) - Body ground
    		 10 kΩ or higher
    Circuit opening relay (2B-8) or F/PMP relay (3) - Body ground
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPAIR OR REPLACE INTEGRATION RELAY

12. INSPECT F/PMP RELAY

  1. A095468
    Remove the F/PMP relay from the engine room J/B and R/B No. 2.

  1. Measure the resistance of the F/PMP relay.

    Standard resistance:
    Tester Connection
    		 Specified Condition
    3 - 4
    		 10 kΩ or higher
    3 - 4
    		 Below 1 Ω
    (when battery voltage applied to terminals 1 and 2)



NG
REPLACE F/PMP RELAY
OK


13. INSPECT FUEL PUMP RESISTER

  1. A072544E01
    Measure the resistance of the fuel pump resistor.

    Standard resistance:
    0.30 to 0.34 Ω at 20°C (68°F)



 NG
REPLACE FUEL PUMP RESISTER
OK


14. CHECK HARNESS AND CONNECTOR (F/PMP RELAY - FUEL PUMP RESISTER)

  1. A107721E12
    Check the harness and the connectors between the F/PMP relay and the fuel pump resistor.

    1. Remove the F/PMP relay from the engine room J/B and R/B No. 2.

    2. Disconnect the fuel pump resistor connector.

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance (Check for open):
      Tester Connection
      		 Specified Condition
      F/PMP relay (4) - Fuel pump resistor (A40-2)
      		 Below 1 Ω
      F/PMP relay (3) - Fuel pump resistor (A40-1)
      		 Below 1 Ω

      Standard resistance (Check for short):
      Tester Connection
      		 Specified Condition
      Fuel pump relay (4) or Fuel pump resistor (A40-2) - Body ground
      		 10 kΩ or higher
      Fuel pump relay (4) or Fuel pump resistor (A40-1) - Body ground
      		 10 kΩ or higher



OK
PROCEED TO NEXT INSPECTION PROCEDURE SHOWN IN PROBLEM SYMPTOMS TABLE
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR


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