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Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: When using the Intelligent tester or Techstream with the power switch OFF to troubleshoot:
Connect the Intelligent tester or Techstream to the vehicle, and turn a courtesy switch on and off at 1.5 second intervals until communication between the tester and vehicle begins.
  1. CLEAR DTC 
    1. Clear the DTC (see DTC CHECK / CLEAR )
  2. CHECK FOR DTC 
    1. Recheck for DTC (see DTC CHECK / CLEAR )

    Result: 

    RESULT REFERENCE

    Result Proceed to
    DTC U1127, U1128 and U1129 output occurs A
    DTC U1127, U1128 or U1129 output occurs B
    No DTC output occurs C

    B: GO TO DTC CHART  (See DIAGNOSTIC TROUBLE CODE CHART )

    C: USE SIMULATION METHOD TO CHECK  (See HOW TO PROCEED WITH TROUBLESHOOTING )

    A: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (OUTER MIRROR SWITCH - NO. 1 CONSOLE SWITCH) 
    Fig 1: Identifying Terminals Of L6 And L75 Switch Connectors
    G04947032Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the L6 and L75 switch connectors
    2. Measure the resistance and voltage according to the value(s) in the table below

    Standard resistance 

    RESISTANCE REFERENCE

    Tester Connection Condition Specified Condition
    L6-7 (MPX) - L75-3 (MPX) Always Below 1 Ω
    L6-7 (MPX) or L75-3 (MPX) - Body ground Always 10 kΩ or higher

    Standard voltage 

    VOLTAGE SPECIFICATION

    Tester Connection Condition Specified Condition
    L6-7 (MPX) or L75-3 (MPX) - Body ground Always Below 1 V

    NG:  Go to step  4

    OK: REPLACE OUTER MIRROR SWITCH  (See REMOVAL )

  4. CLEAR DTC 
    1. Reconnect the L6 switch connector
    2. Clear the DTC (see DTC CHECK / CLEAR )
  5. CHECK FOR DTC 
    1. Disconnect the L75 switch connector.
    2. Recheck for DTC (see DTC CHECK / CLEAR )

    Result: 

    RESULT REFERENCE

    Result Proceed to
    DTC U1127, U1128 and U1129 output occurs A
    DTC U1127 output occurs B

    B: REPLACE NO. 1 CONSOLE SWITCH 

    A: Go to next step 

  6. CLEAR DTC 
    1. Reconnect the L75 switch connector.
    2. Clear the DTC (see DTC CHECK / CLEAR )
  7. CHECK FOR DTC 
    1. Disconnect the e4 ECU connector
    2. Recheck for DTC (see DTC CHECK / CLEAR )

    Result: 

    RESULT REFERENCE

    Result Proceed to
    DTC U1127, U1128 and U1129 output occurs A
    DTC U1128 output occurs B

    B: REPLACE FRONT SEAT CLIMATE CONTROL ECU RH 

    A: Go to next step 

  8. CLEAR DTC 
    1. Reconnect the e4 ECU connector.
    2. Clear the DTC (see DTC CHECK / CLEAR ).
  9. CHECK FOR DTC 
    1. Disconnect the e34 ECU connector.
    2. Recheck for DTC (see DTC CHECK / CLEAR ).

    Result: 

    RESULT REFERENCE

    Result Proceed to
    DTC U1127, U1128 and U1129 output occurs A
    DTC U1129 output occurs B

    B: REPLACE FRONT SEAT CLIMATE CONTROL ECU LH 

    A: REPAIR OR REPLACE HARNESS OR CONNECTOR 

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