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Home >> Lexus >> 2022 >> LS 500h RWD >> Repair and Diagnosis >> Hybrid/Electric Powertrain >> Testing and Diagnosis >> Hybrid Control System (W/ Advanced Park) - Diagnostic Codes (5 Of 5) & Circuit Tests (1 Of 2) >> HYBRID CONTROL SYSTEM (w/ Advanced Park) >> DTC P3123-87: Lost Communication with Drive Motor Control Module "A" from Hybrid/EV Control Module Missing Message [11/2021 - 10/2023] >> Procedure

DTC P3123-87: Lost Communication with Drive Motor Control Module "A" from Hybrid/EV Control Module Missing Message [11/2021 - 10/2023]: Procedure

  1. INSPECT FUSE (IGCT NO. 2) 
    1. Remove the IGCT NO. 2 fuse from the No. 2 Luggage Room Relay Block.
    2. Measure the resistance according to the value(s) in the table below.
      GTY1087230Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 2 Luggage Room Relay Block
      *2 IGCT NO. 2 Fuse

      Standard Resistance

      Tester Connection Condition Specified Condition
      IGCT NO. 2 fuse terminals Always Below 1 Ω
    3. Install the IGCT NO. 2 fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  9

    Result: 

    OK 

    See step  2

  2. CLEAR DTC 

    Refer to PROCEDURE - Step 3

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    See step  3

  3. CHECK DIAGNOSIS RELATED INFORMATION AND DTC OUTPUT (HYBRID CONTROL) 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG) and wait for 2 minutes or more.
    3. Enter the following menus: Powertrain / Hybrid Control / Utility / Diagnosis Related Information.

      Powertrain > Hybrid Control > Utility 

      Tester Display
      Diagnosis Related Information
    4. Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

      Powertrain > Hybrid Control > Trouble Codes 

    5. Check for DTCs.

      Result

      Result  Proceed to
      P3123-87 is listed in Diagnosis Related Information or DTC P3123-87 is output. A
      P3123-87 is not listed in Diagnosis Information and DTC P3123-87 is not output. B
    6. Turn the power switch off.

    Result: 

    B 

    CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS [11/2021 - 10/2023] 

    Result: 

    A 

    See step  4

  4. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU ASSEMBLY CONNECTOR) 

    Refer to PROCEDURE - Step 1

    Result

    Proceed to
    OK
    NG

    Result: 

    NG 

    CONNECT SECURELY 

    Result: 

    OK 

    See step  5

  5. CHECK CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CONNECTOR) 

    Refer to PROCEDURE - Step 3

    Result

    Result Proceed to
    OK A
    NG (The connector is not connected securely.) B
    NG (The terminals are not making secure contact or are deformed, or water or foreign matter exists in the connector.) C

    Result: 

    B 

    CONNECT SECURELY 

    Result: 

    C 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    A 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY POWER SOURCE CIRCUIT) 
    WARNING:

    Be sure to wear insulated gloves.

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

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

    2. Disconnect the A94 inverter with converter assembly connector.

      Refer to REMOVAL [11/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]

    3. Measure the resistance according to the value(s) in the table below.
      GTY783001Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Inverter with Converter Assembly)

      Standard Resistance

      Tester Connection Condition Specified Condition
      A94-30 (GND1) - Body ground Power switch off Below 1 Ω
      A94-31 (GND2) - Body ground Power switch off Below 1 Ω
    4. Connect the cable to the negative (-) auxiliary battery terminal and wait for 2 minutes or more.
    5. Turn the power switch on (IG).
    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A94-10 (+B) - Body ground Power switch on (IG) 11 to 14 V
      A94-11 (+B2) - Body ground Power switch on (IG) 11 to 14 V
      NOTE:

      Turning the power switch on (IG) with the inverter with converter assembly disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    7. Turn the power switch off.
    8. Disconnect the cable from the negative (-) auxiliary battery terminal.
    9. Reconnect the A94 inverter with converter assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - HYBRID VEHICLE CONTROL ECU ASSEMBLY) 
    WARNING:

    Be sure to wear insulated gloves.

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

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

    2. Disconnect the A94 inverter with converter assembly connector.
    3. Disconnect the A107 hybrid vehicle control ECU assembly connector.
    4. Connect the cable to the negative (-) auxiliary battery terminal.
    5. Turn the power switch on (IG).
    6. Measure the voltage according to the value(s) in the table below.
      GTY1086163Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Inverter with Converter Assembly)
      *b Front view of wire harness connector
      (to Hybrid Vehicle Control ECU Assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      A107-2 (HMCL) - Body ground Power switch on (IG) Below 1 V
      A107-13 (HMCH) - Body ground Power switch on (IG) Below 1 V
      NOTE:

      Turning the power switch on (IG) with the hybrid vehicle control ECU assembly connector and the inverter with converter assembly disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    7. Turn the power switch off.
    8. Disconnect the cable from the negative (-) auxiliary battery terminal and wait for 2 minutes or more.
    9. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      A94-6 (HMCL) - A107-2 (HMCL) Power switch off Below 1 Ω
      A94-5 (HMCH) - A107-13 (HMCH) Power switch off Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      A94-6 (HMCL) or A107-2 (HMCL) - Body ground and other terminals Power switch off 10 kΩ or higher
      A94-5 (HMCH) or A107-13 (HMCH) - Body ground and other terminals Power switch off 10 kΩ or higher
    10. Reconnect the A107 hybrid vehicle control ECU assembly connector.
    11. Reconnect the A94 inverter with converter assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. CHECK INVERTER WITH CONVERTER ASSEMBLY (INTERNAL RESISTANCE) 
    WARNING:

    Be sure to wear insulated gloves.

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

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

    2. Disconnect the A94 inverter with converter assembly connector.
    3. Measure the resistance according to the value(s) in the table below.
      GTY1084671Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      A107-2 (HMCL) -A107-13 (HMCH) Power switch off 110 to 130 Ω
    4. Reconnect the A94 inverter with converter assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE INVERTER WITH CONVERTER ASSEMBLY. Refer to  REMOVAL [11/2021 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

    Result: 

    NG 

    REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY. Refer to  REMOVAL [11/2021 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

  9. REPLACE FUSE (IGCT NO. 2) 
    1. Replace the IGCT NO. 2 fuse.
      GTY1087230Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 2 Luggage Room Relay Block
      *2 IGCT NO. 2 Fuse
    2. Turn the power switch on (READY).
    3. Check if there is an open circuit in the IGCT NO. 2 fuse in the No. 2 luggage room relay block.

      OK

      There is no open circuit in the IGCT NO. 2 fuse.

      HINT: 

      If the fuse does not become open again after turning the power switch on (READY), it can be assumed that the previous fuse failed due to age.

    4. Turn the power switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    COMPLETED 

    Result: 

    NG 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - NO. 2 LUGGAGE ROOM RELAY BLOCK) 
    WARNING:

    Be sure to wear insulated gloves.

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

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

    2. Remove the IGCT NO. 2 fuse from the No. 2 luggage room relay block.
    3. Disconnect the A94 inverter with converter assembly connector.
    4. Measure the resistance according to the value(s) in the table below.
      GTY1086757Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 2 Luggage Room Relay Block *2 IGCT NO. 2 Fuse
      *a Front view of wire harness connector
      (to Inverter with Converter Assembly)      		 - -

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      A94-10 (+B), A94-11 (+B2) or 2 (IGCT NO. 2 fuse terminal) - Body ground and other terminals Power switch off 10 kΩ or higher
    5. Reconnect the A94 inverter with converter assembly connector.
    6. Install the IGCT NO. 2 fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  11

  11. REPLACE INVERTER WITH CONVERTER ASSEMBLY 

    Refer to REMOVAL [11/2021 - 10/2022] , or refer to REMOVAL [10/2022 - 10/2023]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (IGCT NO. 2) 

  12. REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (IGCT NO. 2) 

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