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Home >> Lexus >> 2009 >> LS 460L RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - System Testing; Component Inspection, Removal & Installation >> ECM Power Source Circuit >> Inspection Procedure
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Inspection Procedure

  1. INSPECT ECM (+B, +B2 VOLTAGE) 
    1. Turn the engine switch on (IG).
    2. Measure the voltage according to the value (s) in the table below.

      Standard voltage 

      STANDARD VOLTAGE SPECIFICATION

      Tester Connection Switch Condition Specified Condition
      A13-2 (+B) - E3-1 (E1) Engine switch on (IG) 11 to 14 V
      A13-1 (+B2) - E3-1 (E1) Engine switch on (IG) 11 to 14 V
      3. Fig 1: Identifying ECM (+B, +B2 Voltage)
      G06190087Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

  2. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) 
    1. Disconnect the E3 ECM connector.
    2. Measure the resistance according to the value (s) in the table below.

      Standard resistance (Check for open) 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Condition Specified Condition
      E3-1 (E1) - Body ground Always Below 1 Ω
      3. Fig 2: Identifying Terminal E1 Of E3 ECM Connector
      G06190088Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

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

      Standard voltage 

      STANDARD VOLTAGE SPECIFICATION

      Tester Connection Switch Condition Specified Condition
      A14-8 (IGSW) - E3-1 (E1) Engine switch on (IG) 11 to 14 V
      3. Fig 3: Identifying ECM (IGSW Voltage)
      G06190089Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK:  Go to step  6

    NG: Go to Next Step 

  4. CHECK FUSE (ECU-IG) 
    1. Remove the ECU-IG fuse from the engine room No. 2 junction block.
    2. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Condition Specified Condition
      ECU-IG Always Below 1 Ω
      3. Fig 4: Identifying ECU-IG Fuse
      G06190090Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE 

    OK: Go to Next Step 

  5. INSPECT IGNITION RELAY NO. 2 (IG2) 
    1. Remove the IG2 relay from the engine room No. 2 junction block.
    2. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Condition Specified Condition
      3-5 When no battery voltage applied to terminals 1 and 2 10 kΩ or higher
      3-5 When battery voltage applied to terminals 1 and 2 Below 1 Ω
      3. Fig 5: Inspecting Ignition Relay No. 2 (IG2)
      G06190091Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE IGNITION RELAY NO. 2 (IG2)  (See IGNITION RELAY NO. 2 )

    OK: GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START  (See POWER SOURCE MODE DOES NOT CHANGE )

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

      Standard voltage 

      STANDARD VOLTAGE SPECIFICATION

      Tester Connection Switch Condition Specified Condition
      A14-3 (MREL) - E3-1 (E1) Engine switch on (IG) 9 to 14 V
      3. Fig 6: Identifying ECM (MREL Voltage)
      G06190092Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE ECM  (See REMOVAL )

    OK: Go to Next Step 

  7. CHECK FUSE (EFI MAIN2) 
    1. Remove the EFI MAIN2 fuse from the engine room No. 2 relay block.
    2. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Condition Specified Condition
      EFI MAIN2 Always Below 1 Ω
      3. Fig 7: Identifying EFI MAIN2 Fuse
      G06190093Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE 

    OK: Go to Next Step 

  8. INSPECT EFI RELAY (EFI MAIN2) 
    1. Remove the EFI MAIN2 relay from the engine room No. 2 relay block.
    2. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Condition Specified Condition
      3-5 When no battery voltage applied to terminals 1 and 2 10 kΩ or higher
      When battery voltage applied to terminals 1 and 2 Below 1 Ω
    Fig 8: Inspecting EFI Relay (EFI MAIN2)
    G06190094Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPLACE EFI RELAY (EFI MAIN2)  (See EFI RELAY )

    OK: Go to Next Step 

  9. CHECK HARNESS AND CONNECTOR (EFI RELAY (EFI MAIN2) - ECM, BODY GROUND) 
    1. Check the harness and the connectors between the integration relay and the ECM.
      1. Remove the EFI MAIN2 relay from the engine room No. 2 relay block.
      2. Disconnect the A14 ECM connector.
      3. Measure the resistance according to the value (s) in the table below.

        Standard resistance (Check for open) 

        STANDARD RESISTANCE SPECIFICATION

        Tester Connection Condition Specified Condition
        EFI MAIN2 relay (1) - A14-3 (MREL) Always Below 1 Ω

        Standard resistance (Check for short) 

        STANDARD RESISTANCE SPECIFICATION

        Tester Connection Condition Specified Condition
        EFI MAIN2 relay (1) or A14-3 (MREL) - Body ground Always 10 kΩ or higher
    2. Check the harness and the connectors between the EFI MAIN2 relay and body ground.
      1. Remove the EFI MAIN2 relay from the engine room No. 2 relay block.
      2. Measure the resistance according to the value (s) in the table below.
        Fig 9: Identifying EFI MAIN2 Relay And a14 ECM Connector
        G06190095Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Standard resistance (Check for open) 

        STANDARD RESISTANCE SPECIFICATION

        Tester Connection Condition Specified Condition
        EFI MAIN2 relay (2) - Body ground Always Below 1 Ω

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: CHECK AND REPAIR HARNESS OR CONNECTOR (TERMINAL +B OF ECM - BATTERY POSITIVE TERMINAL) 

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