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Home >> Lexus >> 2009 >> LS 460L AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnostic Codes (4 Of 4) >> DTC U0101 Lost Communication with TCM >> Inspection Procedure

Inspection Procedure

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC U0101) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream ON.
    4. Enter the following menus: Powertrain/Engine/Trouble Codes.
    5. Read DTCs.

    Result 

    RESULT REFERENCE

    Display (DTC Output) Proceed to
    U0101 A
    U0101 and other DTCs B

    HINT:

    If any DTCs other than U0101 are output, troubleshoot those DTCs first.

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

    A: Go to Next Step 

  2. INSPECT TCM 
    1. Disconnect the A12 TCM connector.
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value (s) in the table below.

      Standard voltage 

      STANDARD VOLTAGE SPECIFICATION

      Tester Connection Switch Condition Specified Condition
      A12-6 (+B) - Body ground Engine switch on (IG) 11 to 14 V
    4. Disconnect the E5 TCM connector.
    5. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Condition Specified Condition
      E5-7 (E1) - Body ground Always Below 1 Ω
    Fig 1: Identifying E5 And A12 TCM Connectors
    G06190049Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: GO TO TCM POWER SOURCE CIRCUIT  (See TCM POWER SOURCE CIRCUIT )

    OK: Go to Next Step 

  3. CHECK HARNESS AND CONNECTOR (ECM - TCM) 
    1. Disconnect the A13 ECM connector.
    2. Disconnect the A12 TCM 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
      A13-9 (CAN-) - A12-28 (CAN-) Always Below 1 Ω
      A13-10 (CAN+) - A12-18 (CAN+) Always Below 1 Ω

      Standard resistance (Check for short) 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Condition Specified Condition
      A13-9 (CAN-) or A12-28 (CAN-) - Body ground Always 10 kΩ or higher
      A13-10 (CAN+) - A12-18 (CAN+) - Body ground Always 10 kΩ or higher
      4. Fig 2: Identifying A13 And A12 TCM Connectors
      G06190050Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  4. REPLACE ECM 
    1. Replace the ECM (see REMOVAL ).
  5. CHECK WHETHER DTC OUTPUT RECURS (DTC U0101) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG) and turn the Techstream ON.
    3. Enter the following menus: Powertrain/Engine/Trouble Codes.
    4. Read DTCs.

    Result 

    RESULT REFERENCE

    Display (DTC Output) Proceed to
    No output A
    U0101 B

    B: REPLACE TCM  (See REMOVAL )

    A: END 

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