2008 Lexus IS FFACTORY OEM SERVICE PROCEDURE

Inspection Procedure

  1. CHECK FUEL PUMP OPERATION 
    1. Check the fuel pump operation (See ON-VEHICLE INSPECTION ).

    NG: Go to step  5

    OK: Go to next step 

  2. INSPECT F/PMP RELAY 
    1. Remove the F/PMP relay from the engine room No. 2 relay block
    2. Measure the resistance according to the value(s) in the table below

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      3 - 4 When no battery voltage applied to terminals 1 and 2 Below 1 Ω
      3 - 4 When battery voltage applied to terminals 1 and 2 10 kΩ or higher
      Fig 1: Identifying F/Pmp Relay From Engine Room No. 2 Relay Block
      G05285125Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Reinstall the F/PMP relay

    NG: REPLACE F/PMP RELAY 

    OK: Go to next step 

  3. INSPECT FUEL PUMP RESISTOR 
    1. Disconnect the fuel pump resister connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      1 - 2 20°C (68°F) 0.30 to 0.34 Ω
    3. Reconnect the fuel pump resister connector.
      4. Fig 2: Inspecting Fuel Pump Resister
      G04962581Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE FUEL PUMP RESISTOR  (See REMOVAL )

    OK: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (F/PMP RELAY - FUEL PUMP RESISTOR) 
    1. Remove the F/PMP relay from the engine room No. 2 relay block
    2. Disconnect the fuel pump resistor connector
    3. Measure the resistance according to the value(s) in the table below

      Standard Resistance (Check for Open) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      F/PMP relay (4) - Fuel pump resistor (A40-2) Always Below 1 Ω
      F/PMP relay (3) - Fuel pump resistor (A40-1) Always Below 1 Ω

      Standard Resistance (Check for Short) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Fuel pump relay (4) or Fuel pump resistor (A40-2) - Body ground Always 10 kΩ or higher
      Fuel pump relay (3) or Fuel pump resistor (A40-1) - Body ground Always 10 kΩ or higher
    4. Reinstall the F/PMP relay.
    5. Reconnect the fuel pump resister connector.
      6. Fig 3: Identifying Fuel Pump Resistor Connector A40
      G05751810Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE  (See PROBLEM SYMPTOMS TABLE )

  5. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE CIRCUIT OPENING RELAY) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG) and turn the Techstream ON
    3. Enter the following menus: Powertrain / Engine / Active Test / Activate the Fuel Pump Speed Control.
    4. Check the operation of the relay while operating it using the Techstream

      OK: Operating noise can be heard from the relay. 

    NG: Go to step  11

    OK: Go to next step 

  6. INSPECT FUEL PUMP 
    1. Inspect fuel pump resistance.
      1. Remove the fuel pump.
      2. Measure the resistance according to the value(s) in the table below.

        Standard Resistance 

        TESTER CONNECTION SPECIFIED CONDITION CHART

        Tester Connection Condition Specified Condition
        4 - 5 20°C (68°F) 0.2 to 3.0 Ω
    2. Inspect fuel pump operation.
      1. Apply battery voltage to both terminals. Check that the pump operates.
        NOTE:
        • These tests must be done quickly (within 10 seconds) to prevent the coil from burning out.
        • Keep the fuel pump as far away from the battery as possible.
        • Always turn the voltage on and off on the battery side, not the fuel pump side.
          Fig 4: Identifying Fuel Pump Connector
          G05751811Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Reinstall the fuel pump

    NG: REPLACE FUEL PUMP  (See REMOVAL )

    OK: Go to next step 

  7. CHECK HARNESS AND CONNECTOR (FUEL PUMP - F/PMP RELAY AND BODY GROUND) 
    1. 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 No 2 relay block
      3. Measure the resistance according to the value(s) in the table below

        Standard Resistance (Check for Open) 

        TESTER CONNECTION SPECIFIED CONDITION CHART

        Tester Connection Condition Specified Condition
        Fuel pump (Q14-4) - F/PMP relay (4) Always Below 1 Ω

        Standard Resistance (Check for Short) 

        TESTER CONNECTION SPECIFIED CONDITION CHART

        Tester Connection Condition Specified Condition
        Fuel pump (Q14-4) or F/PMP (4) - Body ground Always 10 kΩ or higher
      4. Reinstall the F/PMP relay
    2. Check the harness and the connectors between the fuel pump and body ground
      1. Measure the resistance according to the value(s) in the table below

        Standard Resistance (Check for Open) 

        TESTER CONNECTION SPECIFIED CONDITION CHART

        Tester Connection Condition Specified Condition
        Fuel pump (Q14-5) - Body ground Always 10 kΩ or higher
        Fig 5: Identifying Fuel Pump Connector Q14 And F/Pmp Relay From Engine Room No 2 Relay Block
        G05751812Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Reconnect the fuel pump connector

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  8. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - F/PMP RELAY) 
    1. Remove the integration relay from the engine room No 2 relay block.
    2. Remove the F/PMP relay from the engine room No 2 relay block.
    3. Measure the resistance according to the value(s) in the table below

      Standard Resistance (Check for Open) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Integration relay (2B-8) - F/PMP relay (1) Always Below 1 Ω
      Integration relay (2B-8) - F/PMP relay (3) Always Below 1 Ω

      Standard Resistance (Check for Short) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Circuit opening relay (2B-8) or F/PMP relay (1) - Body ground Always 10 kΩ or higher
      Circuit opening relay (2B-8) or F/PMP relay (3) - Body ground Always 10 kΩ or higher
    4. Reinstall the relays
      5. Fig 6: Identifying Integration Relay From Engine Room No 2 Relay Block
      G05751813Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  9. 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 (Check for Open) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      Fuel pump (Q14-5) - Body ground Always Below 1 Ω
    3. Reconnect the fuel pump connector
      4. Fig 7: Identifying Fuel Pump Connector Q14
      G05751814Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  10. CHECK FUEL LINE 
    1. Check the fuel lines for leaks or blockage

      OK: No leaks or blockage 

    NG: REPAIR OR REPLACE FUEL LINE 

    OK: REPAIR OR REPLACE FUEL SYSTEM (PRESSURE REGULATOR AND FUEL FILTER) 

  11. INSPECT FUSE (F/PMP FUSE) 
    1. Remove the F/PMP fuse from the engine room No. 2 relay block.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      F/PMP fuse Always Below 1 Ω
    3. Reinstall the F/PMP fuse

    NG: CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE (F/PMP FUSE) 

    Fig 8: Identifying F/Pmp Fuse From Engine Room No. 2 Relay Block
    G05751815Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: Go to next step 

  12. INSPECT INTEGRATION RELAY (EFI NO. 2 RELAY) 
    1. Remove the integration relay from the engine room No 2 relay block
    2. Measure the resistance according to the value(s) in the table below

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      2B-4 - 2C-1 When no battery voltage applied to terminals 2B-3 and 2B-2 10 kΩ or higher
      2B-4 - 2C-1 When battery voltage applied to terminals 2B-3 and 2B-2 Below 1 Ω
    3. Reinstall the integration relay.
      4. Fig 9: Identifying Integration Relay From Engine Room No 2 Relay Block
      G05751816Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE INTEGRATION RELAY  (See REMOVAL  )

    OK: Go to next step 

  13. INSPECT INTEGRATION RELAY (C/OPN RELAY) 
    1. Remove the integration relay from the engine room No 2 relay block
    2. Measure the resistance according to the value(s) in the table below

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Condition Specified Condition
      2B-6 - 2B-8 When no battery voltage applied to terminals 2B-6 and 2B-7 10 kΩ or higher
      2B-6 - 2B-8 When battery voltage applied to terminals 2B-6 and 2B-7 Below 1 Ω
    3. Reinstall the integration relay
      4. Fig 10: Identifying Integration Relay From Engine Room No 2 Relay Block
      G05751816Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE INTEGRATION RELAY  (See REMOVAL  )

    OK: Go to next step 

  14. INSPECT ECM (FC VOLTAGE) 
    1. Turn the engine switch on (IG).
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Switch Condition Specified Condition
      A5-5 (FC) - E6-1 (E1) Engine Switch on (IG) 11 to 14 V
      3. Fig 11: Identifying ECM Connector E6 And A5
      G05751818Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: CHECK AND REPAIR HARNESS AND CONNECTOR (ECM - C/OPN RELAY) 

    OK: REPLACE ECM  (See REMOVAL  )

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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