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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 U11B3-87: Lost Communication with Hybrid/EV Powertrain Control Module (ch5) Missing Message [09/2023 - ] >> Procedure

DTC U11B3-87: Lost Communication with Hybrid/EV Powertrain Control Module (ch5) 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  9

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU ASSEMBLY - TCM) 

    Pre-procedure1

    • Disconnect the hybrid vehicle control ECU 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
      B21-2 (CA5H) - C25-15 (CANU) Always Below 1 Ω Ω
      B21-1 (CA5L) - C25-16 (CAND) Always Below 1 Ω Ω
      B21-2 (CA5H) or C25-15 (CANU) - Body ground and other terminals Always 10 kΩ or higher kΩ
      B21-1 (CA5L) 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 HYBRID VEHICLE CONTROL ECU ASSEMBLY (+B1, +B2 VOLTAGE) 

    Pre-procedure1

    • Turn the ignition switch to ON.
    • Measure the voltage according to the value(s) in the table below.
      GTY1231099Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU Assembly)      		 - -

      Standard Voltage

      Tester Connection Condition Specified Condition Result
      D44-8 (+B1) - Body ground Ignition switch ON 11 to 14 V V
      B21-10 (+B2) - Body ground Ignition switch ON 11 to 14 V V

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Turn the ignition switch off.

    Result: 

    NG 

    REPAIR OR REPLACE ECU POWER SOURCE CIRCUIT. Refer to  ECU Power Source Circuit [09/2023 - ] 

    Result: 

    OK 

    See step  4

  4. CHECK TERMINAL VOLTAGE (IGR VOLTAGE) 

    Pre-procedure1

    • Turn the ignition switch to ON.
    • Measure the voltage according to the value(s) in the table below.
      GTY1227775Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU Assembly)      		 - -

      Standard Voltage

      Tester Connection Switch Condition Specified Condition Result
      B21-8 (IGR) - D44-1 (E1) Ignition switch ON 11 to 14 V V

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Turn the ignition switch off.

    Result: 

    NG 

    REPAIR OR REPLACE ECU POWER SOURCE CIRCUIT. Refer to  DTC P2533-14: Ignition Switch On/Start Position Circuit Low Circuit Short to Ground or Open [09/2023 - ] 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU ASSEMBLY - BODY GROUND) 

    Pre-procedure1

    • Disconnect the hybrid vehicle control ECU assembly connectors.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      D44-1 (E1) - Body ground Always Below 1 Ω Ω
      B21-12 (E01) - Body ground Always Below 1 Ω Ω
      B21-24 (E12) - Body ground Always Below 1 Ω Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Reconnect the hybrid vehicle control ECU assembly connectors.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY 

    HINT: 

    Refer to REMOVAL [09/2023 - 12/2023] , or refer to REMOVAL [12/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  7

  7. 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  8

  8. CHECK DTC OUTPUT (DTC U11B3-87) 

    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
      U11B3-87 is output A
      DTCs are not output B

    Post-procedure1

    • None.

    Result: 

    A 

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

    Result: 

    B 

    END 

  9. 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  10

  10. 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  11

  11. 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  12

  12. 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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