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Home >> Lexus >> 2024 >> TX 350 Base, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 94 (Hybrid Transaxle System (Pc60) - Diagnostic Codes (4 Of 4) & Circuit Tests) >> Hybrid Transaxle System >> 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 TCM connector.
    • 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 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None.

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (HYBRID MOTOR CONTROL INVERTER ASSEMBLY - TCM) 
    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 hybrid motor control inverter assembly connector.
    • Disconnect the TCM connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      C46-15 (HMH2) - C25-15 (CANU) Always Below 1 Ω Ω
      C46-14 (HML2) - C25-16 (CAND) Always Below 1 Ω Ω
      C46-15 (HMH2) or C25-15 (CANU) - Body ground and other terminals Always 10 kΩ or higher kΩ
      C46-14 (HML2) or C25-16 (CAND) - 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) 
    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 hybrid motor control inverter assembly connector.
    • Remove the IGCT NO. 1 relay from the No. 1 engine room relay block assembly.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      C46-10 (IGC1) - 5 (IGCT NO. 1 relay holder) Ignition switch off Below 1 Ω Ω
      C46-11 (IGC2) - 5 (IGCT NO. 1 relay holder) Ignition switch off Below 1 Ω Ω
      C46-30 (GND1) - Body ground Ignition switch off Below 1 Ω Ω
      C46-31 (GND2) - Body ground Ignition switch off Below 1 Ω Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Install the IGCT NO. 1 relay.
    • Reconnect the hybrid motor control inverter assembly connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. REPLACE 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 > Transmission > 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 DTC OUTPUT (DTC U117E-87) 

    Pre-procedure1

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

      Powertrain > Transmission > Trouble Codes 

      Result

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

    Post-procedure1

    • None.

    Result: 

    A 

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

    Result: 

    B 

    END 

  7. CHECK HYBRID MOTOR CONTROL INVERTER ASSEMBLY 
    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 hybrid motor control inverter 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
      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 kΩ or higher kΩ
      C46-15 (HMH2) or C46-14 (HML2) - Body ground and other terminals Cable disconnected from negative (-) auxiliary battery terminal 200 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None.

    Result: 

    OK 

    REPLACE 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 kΩ or higher kΩ

      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 ECM 

    Pre-procedure1

    • Disconnect the cable from the negative (-) auxiliary battery terminal.
    • Disconnect the ECM 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
      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 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None.

    Result: 

    OK 

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

    Result: 

    NG 

    See step  10

  10. CHECK EV MOTOR CONTROL INVERTER ASSEMBLY 
    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 EV motor control inverter 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
      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 kΩ or higher kΩ
      J72-34 (HMH4) or J72-35 (HML4) - Body ground and other terminals Cable disconnected from negative (-) auxiliary battery terminal 200 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • None.

    Result: 

    OK 

    REPLACE EV MOTOR CONTROL INVERTER ASSEMBLY. Refer to  REMOVAL [09/2023 - 12/2023]  , or refer to  REMOVAL [12/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (ML-BUS) 

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