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Home >> Lexus >> 2008 >> LS 600hL >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTC P1340 - P3190, DTC U0293 >> DTC P1438: HCAC System Variable Valve Circuit Low >> Inspection Procedure
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Inspection Procedure

  1. CHECK HCAC VSV (POWER SOURCE) 
    1. Disconnect the HCAC VSV connector.
    2. Turn the power switch ON (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      STANDARD VOLTAGE

      Tester Connection Switch Condition Specified Condition
      E57-2 - Body ground Power switch ON (IG) 11 to 14 V
      Fig 1: Identifying HCAC VSV Connector Terminals
      G05771073Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG:  Go to step  5

    OK: Go to next step 

  2. INSPECT HCAC VSV 
    1. Inspect the HCAC VSV (See INSPECTION ).

    NG: REPLACE HCAC VSV  (See INSPECTION )

    OK: Go to next step 

  3. CHECK HCAC VSV (POWER SOURCE) 
    1. Connect the HCAC VSV connector.
    2. Turn the power switch ON (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      STANDARD VOLTAGE

      Tester Connection Switch Condition Specified Condition
      A13-35 (HCC1) - Body ground Power switch ON (IG) 11 to 14 V
      Fig 2: Identifying ECM Connector Terminals
      G05771074Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: Go to step 4 

    OK: REPLACE ECM  (See REMOVAL )

  4. CHECK HARNESS AND CONNECTOR (HCAC VSV - ECM) 
    1. Disconnect the E57 HCAC VSV connector.
    2. Disconnect the A13 ECM connector.
    3. Measure the resistance according to the value(s) in table below.

      Standard resistance 

      STANDARD RESISTANCE

      Tester Connection Condition Specified Condition
      E57-1 - A13-35 (HCC1) Always Below 1 Ω
      E57-1 or A13-35 (HCC1) - Body ground Always 10 kΩ or higher
      Fig 3: Identifying HCAC VSV And ECM Connector Terminals
      G05771041Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: REPLACE ECM  (See REMOVAL )

  5. INSPECT FUSE (EFI AND EFI MAIN NO. 1) 
    1. Remove the EFI and EFI MAIN2 fuses from the engine room No. 2 junction block
      2. Fig 4: Identifying EFI And EFI MAIN2 Fuses
      G05771076Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE

      Tester Connection Condition Specified Condition
      EFI fuse Always Below 1 Ω
      EFI MAIN2 fuse Always Below 1 Ω

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

    OK: Go to next step 

  6. INSPECT EFI RELAY (EFI MAIN2) 
    1. Inspect the EFI MAIN2 relay (see ON-VEHICLE INSPECTION ).

    NG: REPLACE EFI MAIN2 RELAY  (See ON-VEHICLE INSPECTION )

    OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (HCAC VSV - BATTERY) 

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