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Home >> Lexus >> 2024 >> TX 350 Base, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 106 (Engine Control System - Diagnostic Codes (7 Of 7) & Symptom Tests (1 Of 2)) >> SFI SYSTEM (for 1Motor-HEV Model) >> DTC U117E-87: Lost Communication with Drive Motor Control Module "A" (ch4) Missing Message [09/2023 - ] >> Procedure

DTC U117E-87: Lost Communication with Drive Motor Control Module "A" (ch4) Missing Message [09/2023 - ]: Procedure

WARNING: This page is about a different car, the 2024 Lexus TX 500h. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK CAN COMMUNICATION LINE (ML-BUS) 

    Pre-procedure1

    • Disconnect the cable from the negative (-) auxiliary battery terminal.
    • Disconnect the ECM connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      B77-18 (CFDP) - B77-17 (CFDN) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Ω
      B77-18 (CFDP) or B77-17 (CFDN) - Other power supply terminals Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher kΩ
      B77-18 (CFDP) or B77-17 (CFDN) - Body ground and other terminals Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (FRONT MOTOR GENERATOR CONTROL ECU - ECM) 
    WARNING:

    Be sure to wear insulated gloves.

    Pre-procedure1

    • Check that the service plug grip is not installed.
      NOTE:

      After removing the service plug grip, do not turn the ignition switch to ON (READY), unless instructed by the service information because this may cause a malfunction.

    • Disconnect the front motor generator control ECU connector.
    • Disconnect the ECM connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      C46-12 (HMH1) - B77-18 (CFDP) Always Below 1 Ω Ω
      C46-13 (HML1) - B77-17 (CFDN) Always Below 1 Ω Ω
      C46-12 (HMH1) or B77-18 (CFDP) - Body ground and other terminals Always 10 kΩ or higher kΩ
      C46-13 (HML1) or B77-17 (CFDN) - Body ground and other terminals Always 10 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (HYBRID MOTOR CONTROL INVERTER ASSEMBLY - IGCT NO. 1 RELAY) 

    HINT: 

    Refer to PROCEDURE - Step 4

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. REPLACE FRONT MOTOR GENERATOR CONTROL ECU (HYBRID MOTOR CONTROL INVERTER ASSEMBLY) 

    HINT: 

    Refer to REMOVAL [09/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  5

  5. CLEAR DTC 

    Pre-procedure1

    • None
    • Clear the DTCs.

      Powertrain > Engine > Clear DTCs 

      Result

      Proceed to
      NEXT

    Post-procedure1

    • Turn the ignition switch off and wait for at least 30 seconds.

    Result: 

    NEXT 

    See step  6

  6. CHECK WHETHER DTC OUTPUT RECURS (DTC U117E-87) 

    Pre-procedure1

    • Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    • Read the DTCs.

      Powertrain > Engine > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output A
      U117E-87 is output B

    Post-procedure1

    • None

    Result: 

    A 

    END 

    Result: 

    B 

    REPLACE ECM. Refer to  REMOVAL [09/2023 - ] 

  7. CHECK FRONT MOTOR GENERATOR CONTROL ECU 
    WARNING:

    Be sure to wear insulated gloves.

    Pre-procedure1

    • Check that the service plug grip is not installed.
      NOTE:

      After removing the service plug grip, do not turn the ignition switch to ON (READY), unless instructed by the service information because this may cause a malfunction.

    • Disconnect the cable from the negative (-) auxiliary battery terminal.
    • Disconnect the front motor generator control ECU connector.

      HINT: 

      Check the other ECUs are connected.

    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      C46-12 (HMH1) - C46-13 (HML1) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Ω
      C46-15 (HMH2) - C46-14 (HML2) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Ω
      C46-12 (HMH1) or C46-13 (HML1) - Other power supply terminals Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher kΩ
      C46-15 (HMH2) or C46-14 (HML2) - Other power supply terminals Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher kΩ
      C46-12 (HMH1) or C46-13 (HML1) - Body ground and other terminals Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Ω
      C46-15 (HMH2) or C46-14 (HML2) - Body ground and other terminals Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    OK 

    REPLACE FRONT MOTOR GENERATOR CONTROL ECU (HYBRID MOTOR CONTROL INVERTER ASSEMBLY). Refer to  REMOVAL [09/2023 - ] 

    Result: 

    NG 

    See step  8

  8. CHECK HYBRID VEHICLE CONTROL ECU ASSEMBLY 

    Pre-procedure1

    • Disconnect the cable from the negative (-) auxiliary battery terminal.
    • Disconnect the hybrid vehicle control ECU assembly connector.

      HINT: 

      Check the other ECUs are connected.

    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      B21-2 (CA5H) - B21-1 (CA5L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω Ω
      B21-2 (CA5H) or B21-1 (CA5L) - Other power supply terminals Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher kΩ
      B21-2 (CA5H) or B21-1 (CA5L) - Body ground and other terminals Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    OK 

    REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY. Refer to  REMOVAL [09/2023 - 12/2023]  , or refer to  REMOVAL [12/2023 - ] 

    Result: 

    NG 

    See step  9

  9. CHECK TCM 

    Pre-procedure1

    • Disconnect the cable from the negative (-) auxiliary battery terminal.
    • Disconnect the TCM connector.

      HINT: 

      Check the other ECUs are connected.

    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      C25-15 (CANU) - C25-16 (CAND) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Ω
      C25-15 (CANU) or C25-16 (CAND) - Other power supply terminals Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher kΩ
      C25-15 (CANU) or C25-16 (CAND) - Body ground and other terminals Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    OK 

    REPLACE TCM. Refer to  REMOVAL [09/2023 - ] 

    Result: 

    NG 

    See step  10

  10. CHECK REAR MOTOR GENERATOR CONTROL ECU 
    WARNING:

    Be sure to wear insulated gloves.

    Pre-procedure1

    • Check that the service plug grip is not installed.
      NOTE:

      After removing the service plug grip, do not turn the ignition switch to ON (READY), unless instructed by the service information because this may cause a malfunction.

    • Disconnect the cable from the negative (-) auxiliary battery terminal.
    • Disconnect the rear motor generator control ECU connector.

      HINT: 

      Check the other ECUs are connected.

    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      J72-32 (HMH3) - J72-33 (HML3) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Ω
      J72-34 (HMH4) - J72-35 (HML4) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Ω
      J72-32 (HMH3) or J72-33 (HML3) - Other power supply terminals Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher kΩ
      J72-34 (HMH4) or J72-35 (HML4) - Other power supply terminals Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher kΩ
      J72-32 (HMH3) or J72-33 (HML3) - Body ground and other terminals Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Ω
      J72-34 (HMH4) or J72-35 (HML4) - Body ground and other terminals Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None

    Result: 

    OK 

    REPLACE REAR MOTOR GENERATOR CONTROL ECU (EV MOTOR CONTROL INVERTER ASSEMBLY). Refer to  REMOVAL [09/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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