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Inspection Procedure

NOTE: When using the Techstream with the engine switch off to troubleshoot: Connect the Techstream to the vehicle, and turn a courtesy switch on and off at 1.5 second intervals until communication between the Techstream 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 TABLE

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

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

    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 & 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 

    TESTER CONNECTION SPECIFIED CONDITION TABLE

    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 

    TESTER CONNECTION SPECIFIED CONDITION TABLE

    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 TABLE

    Result Proceed to
    DTC U1127, U1128 and U1129 are output A
    DTC U1127 is output 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 TABLE

    Result Proceed to
    DTC U1127, U1128 and U1129 are output A
    DTC U1128 is output 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 TABLE

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

    B: REPLACE FRONT SEAT CLIMATE CONTROL ECU LH 

    A: REPAIR OR REPLACE HARNESS OR CONNECTOR 

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