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Home >> Lexus >> 2024 >> TX 350 Base, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 17 (Hybrid Control System - Diagnostic Codes (6 Of 6) & Circuit Tests) >> HYBRID CONTROL SYSTEM (for PHEV Model) >> DTC U115E-87: Lost Communication with Drive Motor Control Module "B" (ch3) Missing Message [12/2023 - ] >> Procedure

DTC U115E-87: Lost Communication with Drive Motor Control Module "B" (ch3) Missing Message [12/2023 - ]: Procedure

WARNING: This page is about a different car, the 2024 Lexus TX 550h+. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK CAN COMMUNICATION LINE (ML-BUS) 
    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.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      B88-2 (CA5H) - B88-1 (CA5L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω Ω
      B88-2 (CA5H) or B88-1 (CA5L) - Other power source terminals Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher kΩ
      B88-2 (CA5H) or B88-1 (CA5L) - Other terminals and body ground Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Reconnect the cable from the negative (-) auxiliary battery terminal.

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  2

  2. INSPECT EV MOTOR CONTROL INVERTER ASSEMBLY (+BR1, +BR2 VOLTAGE) 
    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 EV motor control inverter assembly connector.
    • Reconnect the cable from the negative (-) auxiliary battery terminal.
    • Turn the ignition switch to ON.
    • Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition Result
      J72-10 (+BR1) - Body ground Ignition switch ON 11 to 14 V V
      J72-11 (+BR2) - Body ground Ignition switch ON 11 to 14 V V

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Turn the ignition switch off.
    • Disconnect the cable from the negative (-) auxiliary battery terminal.
    • Reconnect the EV motor control inverter assembly connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (EV MOTOR CONTROL INVERTER ASSEMBLY - BODY GROUND) 
    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 EV motor control inverter assembly connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      J72-30 (GNR1) - Body ground Ignition switch off Below 1 Ω Ω
      J72-31 (GNR2) - Body ground Ignition switch off Below 1 Ω Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Reconnect the EV motor control inverter assembly connector.

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  4

  4. REPLACE EV MOTOR CONTROL INVERTER ASSEMBLY 

    HINT: 

    Refer to REMOVAL [12/2023 - ]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  5

  5. CLEAR DTC 

    Refer to PROCEDURE - Step 3

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  6

  6. CHECK DTC OUTPUT (HYBRID CONTROL) 

    Pre-procedure1

    • Turn the ignition switch to ON and wait for 2 minutes or more.
    • Read the DTCs.

      Powertrain > Hybrid Control > Trouble Codes 

      Result

      Result Proceed to
      U115E-87 is output. A
      U115E-87 is not output. B

    Post-procedure1

    • None

    Result: 

    A 

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

    Result: 

    B 

    END 

  7. INSPECT HYBRID VEHICLE CONTROL ECU ASSEMBLY 

    Pre-procedure1

    • Disconnect the cable to 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
      B88-2 (CA5H) - B88-1 (CA5L) Disconnect the cable to the negative (-) auxiliary battery terminal 108 to 132 Ω Ω
      B88-2 (CA5H) or B88-1 (CA5L) - Other power source terminals Disconnect the cable to the negative (-) auxiliary battery terminal 6 kΩ or higher kΩ
      B88-2 (CA5H) or B88-1 (CA5L) - Other terminals and body ground Disconnect the cable to the negative (-) auxiliary battery terminal 200 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

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

    Result: 

    OK 

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

    Result: 

    NG 

    See step  8

  8. 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
      B89-3 (HMH1) - B89-4 (HML1) Disconnect the cable to the negative (-) auxiliary battery terminal 108 to 132 Ω Ω
      B89-3 (HMH1) or B89-4 (HML1) - Other power source terminals Disconnect the cable to the negative (-) auxiliary battery terminal 6 kΩ or higher kΩ
      B89-3 (HMH1) or B89-4 (HML1) - Other terminals and body ground Disconnect the cable to the negative (-) auxiliary battery terminal 200 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Reconnect the hybrid motor control inverter assembly connector.
    • Reconnect the cable from the negative (-) auxiliary battery terminal.

    Result: 

    OK 

    REPLACE HYBRID MOTOR CONTROL INVERTER ASSEMBLY. Refer to  REMOVAL [12/2023 - ] 

    Result: 

    NG 

    See step  9

  9. CHECK HARNESS AND CONNECTOR 
    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 vehicle control ECU assembly connector.
    • Disconnect the hybrid motor control inverter assembly connector.
    • Disconnect the EV motor control inverter assembly connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      B89-3 (HMH1) - J72-32 (HMH3) Ignition switch off Below 1 Ω Ω
      B89-4 (HML1) - J72-33 (HML3) Ignition switch off Below 1 Ω Ω
      B88-2 (CA5H) - J72-34 (HMH4) Ignition switch off Below 1 Ω Ω
      B88-1 (CA5L) - J72-35 (HML4) Ignition switch off Below 1 Ω Ω
      B89-3 (HMH1) or J72-32 (HMH3) - Body ground and other terminals Ignition switch off 10 kΩ or higher kΩ
      B89-4 (HML1) or J72-33 (HML3) - Body ground and other terminals Ignition switch off 10 kΩ or higher kΩ
      B88-2 (CA5H) or J72-34 (HMH4) - Body ground and other terminals Ignition switch off 10 kΩ or higher kΩ
      B88-1 (CA5L) or J72-35 (HML4) - Body ground and other terminals Ignition switch off 10 kΩ or higher kΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Reconnect the EV motor control inverter assembly connector.
    • Reconnect the hybrid motor control inverter assembly connector.
    • Reconnect the hybrid vehicle control ECU assembly connector.

    Result: 

    OK 

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

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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