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Home >> Lexus >> 2018 >> LS 500 Base, AWD >> Repair and Diagnosis (Single Page) >> Transmission >> Transmission Control Systems >> Electronic A/T Shift Lever System (Aga0F) - Diagnostic Codes (5 Of 5), Circuit & Symptom Tests (1 Of 2) >> Electronic Shift Lever System >> DTC U0103-87: Lost Communication with Gear Shift Control Module "A" Missing Message [12/2017 - 10/2020] >> Procedure

DTC U0103-87: Lost Communication with Gear Shift Control Module "A" Missing Message [12/2017 - 10/2020]: Procedure

  1. CHECK DTC OUTPUT (HEALTH CHECK) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Enter the following menus: Health Check.
    4. Check for DTCs.

      Result

      Result Proceed to
      DTC P176D-12 does not output. A
      DTC P176D-12 is output. B
    5. Turn the engine switch off.

    Result: 

    GO TO DTC CHART (P176D-12). Refer to  DTC P176D-12: IG2 Signal (Gear Shift Control Module "A") Circuit Short to Battery [12/2017 - 10/2023] 

    Result: 

    See step  2

  2. CHECK CONNECTOR CONNECTION CONDITION (SHIFT CONTROL ECU CONNECTOR) 
    1. Check the connector connections and contact pressure of the relevant terminals for the shift control ECU connectors.
      GTY799322Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [12/2017 - ]

      OK

      The connectors are connected securely and there are no contact pressure problems.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT SECURELY 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (SHIFT CONTROL ECU - ECM) 
    1. Disconnect the G81 shift control ECU connector.
    2. Disconnect the A95 ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Switch Condition Specified Condition
      G81-6(CA2H) - A95-26(CANP) Engine switch off Below 1 Ω
      G81-5(CA2L) - A95-25(CANN) Engine switch off Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Switch Condition Specified Condition
      G81-6(CA2H) or A95-26(CANP) - Body ground and other terminals Engine switch off 10 kΩ or higher
      G81-5(CA2L) or A95-25(CANN) - Body ground and other terminals Engine switch off 10 kΩ or higher
    4. Reconnect the A95 ECM connector.
    5. Reconnect the G81 shift control ECU connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. CHECK ECM 
    1. Check that the voltage between the terminals of the sub-battery module assembly is 0 V.
      GTY816277Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the cable from the negative (-) battery terminal.
    3. Disconnect the G81 shift control ECU connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G81-6(CA2H) - G81-5(CA2L) 20°C (68°F) 108 to 132 kΩ
    5. Reconnect the G81 shift control ECU connector.
    6. Connect the cable to the negative (-) battery terminal.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE SHIFT CONTROL ECU. Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020] 

    Result: 

    NG 

    REPLACE ECM. Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020]