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Home >> Lexus >> 2007 >> ES 350 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTC P0606 - P2A03, DTC U0101 >> DTC U0101: Lost Communication with TCM >> Inspection Procedure

Inspection Procedure

  1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC U0101) 
    1. Connect the intelligent tester to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the tester on.
    4. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
    5. Read the DTCs.

      Result 

      RESULT REFERENCE

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

    B: GO TO  DIAGNOSTIC TROUBLE CODE TABLE 

    A: Go to Next Step 

  2. CHECK TCM TERMINAL VOLTAGE (+B AND E1 TERMINALS) 
    1. Disconnect the TCM connector.
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      VOLTAGE SPECIFICATION TABLE

      Tester Connection Specified Condition
      B40-18 (+B) - B40-8 (E1) 9 to 14 V
    4. Turn the engine switch off.
    5. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE REFERENCE TABLE

      Tester Connection Specified Condition
      B40-8 (E1) - Body ground Below 1 Ω
      Fig 1: TCM Connector Terminal Identification
      G05247812Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next Step 

  3. CHECK HARNESS AND CONNECTOR 
    1. Disconnect the B40 TCM connector.
    2. Disconnect the B12 ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE REFERENCE TABLE

      Tester Connection Specified Condition
      B40-6 (CAN+) - B12-2 (CAN+) Below 1 Ω
      B40-7 (CAN-) - B12-1 (CAN-) Below 1 Ω
      B40-6 (CAN+) or B12-2 (CAN+) - Body ground 1 MΩ or more
      B40-7 (CAN-) or B12-1 (CAN-) - Body ground 1 MΩ or more
      Fig 2: Identifying B12 ECM Connector Terminals & B40 TCM Connector Terminals
      G04973750Courtesy 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 ).
      NOTE: Replace the ECM with an ECM from a normally functioning vehicle of the same model.
  5. CHECK IF DTC RECURS 
    1. Connect the intelligent tester to the DLC3.
    2. Clear the DTC.
    3. Start the engine.
    4. Read the DTCs.

      Result 

      RESULT REFERENCE

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

    B: REPLACE ECM (See  REMOVAL  ) 

    A: REPLACE TCM (See  REMOVAL  ) 

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