2008 Lexus ES 350FACTORY OEM SERVICE PROCEDURE

Inspection Procedure

  1. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) 
    1. Disconnect the B12 ECM connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      E1 (B12-81) - Body ground Below 1 Ω
      Fig 1: Identifying Terminals Of B12 ECM Connector
      G05247848Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Reconnect the ECM connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step. 

  2. CHECK ENGINE ROOM JUNCTION BLOCK (EFI RELAY VOLTAGE) 
    1. Remove the engine room junction block from the engine room R/B.
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      1E-6 - Body ground 9 to 14 V
      Fig 2: Identifying Engine Room Junction Block
      G04973797Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK:  Go to step  5

    NG: Go to next step. 

  3. INSPECT EFI MAIN FUSE 
    1. Remove the EFI MAIN fuse from the engine room R/B.
    2. Measure the EFI MAIN fuse resistance.

      Standard Resistance: 

      Below 1 Ω 

    3. Reinstall the EFI MAIN fuse.
      Fig 3: Identifying EFI Main Fuse
      G04973798Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE EFI MAIN FUSE 

    OK: Go to next step. 

  4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - BATTERY) 
    1. Disconnect the negative battery terminal.
    2. Disconnect the positive battery terminal.
    3. Remove the engine room junction block from the engine room R/B.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for open) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      1G-1 - Positive battery terminal Below 1 Ω

      Standard Resistance (Check for short) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      1G-1 or Positive battery terminal - Body ground 10 kΩ or higher
      Fig 4: Identifying Engine Room Junction Block
      G04973799Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    5. Reinstall the engine room junction block.
    6. Reconnect the positive battery terminal.
    7. Reconnect the negative battery terminal.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

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

  5. INSPECT ENGINE ROOM JUNCTION BLOCK (EFI RELAY) 
    1. Remove the engine room junction block from the engine room R/B.
    2. Measure the resistance between the terminals.

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      1E-6 - 1E-12 10 kΩ or higher
      1E-6 - 1E-12 Below 1 Ω (Apply battery voltage between terminals 1E-9 and 1E-11)
      Fig 5: Identifying Engine Room Junction Block
      G04973482Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Reinstall the engine room junction block.

    NG: REPLACE ENGINE ROOM JUNCTION BLOCK 

    OK: Go to next step. 

  6. INSPECT EFI NO. 2 FUSE 
    1. Remove the EFI No. 2 fuse from the engine room R/B.
    2. Measure the EFI No. 2 fuse resistance.

      Standard Resistance: 

      Below 1 Ω 

    3. Reinstall the EFI No. 2 fuse.
      Fig 6: Identifying EFI No. 2 Fuse
      G05835566Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE EFI NO. 2 FUSE 

    OK: Go to next step. 

  7. CHECK HARNESS AND CONNECTOR (ECM - ENGINE ROOM JUNCTION BLOCK) 
    1. Disconnect the A10 ECM connector.
    2. Remove the engine room junction block from the engine room R/B.
    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 Specified Condition
      1E-6 - +B (A10-2) Below 1 Ω
      1E-6 - +B2 (A10-1) Below 1 Ω

      Standard Resistance (Check for short) 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      1E-6 or +B (A10-2) - Body ground 10 kΩ or higher
      1E-6 or +B2 (A10-1) - Body ground 10 kΩ or higher
    4. Reinstall the engine room junction block.
    5. Reconnect the ECM connector.
      Fig 7: Identifying A10 ECM Connector And Engine Room Junction Block 1E Connector
      G05247854Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step. 

  8. INSPECT ECM (IGSW VOLTAGE) 
    1. Disconnect the A10 ECM connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      IGSW (A10-28) - Body ground 9 to 14 V
      Fig 8: Identifying Terminals Of A10 ECM Connector
      G05247855Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Reconnect the ECM connector.

    OK:  Go to step  11

    NG: Go to next step. 

  9. INSPECT IGNITION RELAY NO. 2 
    1. Remove the IG2 relay from the engine room R/B.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      3 - 5 10 kΩ or higher
      3 - 5 Below 1 Ω (Apply battery voltage between terminals 1 and 2)
      Fig 9: Identifying Ignition Relay No. 2 Terminals
      G04942976Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Reinstall the IG2 relay.

    NG: REPLACE IGNITION RELAY NO. 2 

    OK: Go to next step. 

  10. CHECK HARNESS AND CONNECTOR (IG2 RELAY - BODY GROUND) 
    1. Remove the IG2 relay from the engine room R/B.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      IG2 relay terminal 2 - Body ground Below 1 Ω
    3. Reinstall the IG2 relay.

      Result 

      RESULT CHART

      Result Proceed to
      OK A
      NG B
      Fig 10: Identifying IG2 Relay
      G04973805Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    A:  GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START

    B: REPAIR OR REPLACE HARNESS OR CONNECTOR 

  11. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) 
    1. Disconnect the A10 ECM connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      MREL (A10-44) - Body ground Below 1 Ω
      Fig 11: Identifying Terminals Of A10 ECM Connector
      G05247858Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Reconnect the ECM connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    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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