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Home >> Toyota >> 2018 >> Prius Two Eco >> Repair and Diagnosis >> Hybrid/Electric Powertrain >> Testing and Diagnosis >> Hybrid Control System (Nickel Metal Hydride) - Diagnostic Codes (6 Of 8) >> HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY) >> DTC P3123-87: Lost Communication with Drive Motor Control Module "A" from Hybrid/EV Control Module Missing Message [11/2015 -] >> Procedure

DTC P3123-87: Lost Communication with Drive Motor Control Module "A" from Hybrid/EV Control Module Missing Message [11/2015 -]: Procedure

  1. INSPECT FUSE (PCU FR) 
    1. Remove the PCU FR fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Measure the resistance according to the value(s) in the table below.
      GTY573547Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 PCU FR Fuse

      Standard Resistance

      Tester Connection Condition Specified Condition
      PCU FR fuse Always Below 1 Ω
    3. Install the PCU FR fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  10

    Result: 

    OK 

    See step  2

  2. CLEAR DTC 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.
    4. Clear the DTCs.

      Powertrain > Hybrid Control > Clear DTCs 

    5. Turn the power switch off and wait for 2 minutes or more.

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  3

  3. CHECK DIAGNOSIS RELATED INFORMATION (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. Check for Diagnosis Related Information.

      Result

      Result  Proceed to
      Diagnosis Related Information P3123-87 is not output A
      Diagnosis Related Information P3123-87 is output B
    5. Turn the power switch off.

    Result: 

    B 

    See step  7

    Result: 

    A 

    See step  4

  4. CHECK 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 / Trouble Codes.
    4. Check for DTCs.

      Powertrain > Hybrid Control > Trouble Codes 

      Result

      Result  Proceed to
      P3123-87 is output A
      P3123-87 is not output B
    5. Turn the power switch off.

    Result: 

    B 

    CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS [11/2015 -] 

    Result: 

    A 

    See step  5

  5. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR) 
    1. Check the connector connections and contact pressure of the relevant terminals for the hybrid vehicle control ECU connectors.

      HINT: 

      Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [11/2015 -]

      GTY542745Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      OK

      The connectors are connected securely and there are no contact pressure problems.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    CONNECT SECURELY 

    Result: 

    OK 

    See step  6

  6. CHECK CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CONNECTOR) 
    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. Check the connection condition of the low voltage connectors of the inverter with converter assembly and the contact pressure of each terminal. Check the terminals for deformation, and the connector for water and foreign matter.

      HINT: 

      Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [11/2015 -]

      GTY542682Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE:

      Before disconnecting the connector, confirm that it is properly connected by checking that the claws of the lock levers are engaged and that the connector cannot be pulled off.

      OK

      - The connector is connected securely.

      - The terminals are not deformed and are connected securely.

      - No water or foreign matter in the connector.

      HINT: 

      When connecting the connector, connect it with the lock levers raised. Rotate each lock lever downward and make sure that the connector is securely connected. When a lock lever is fully lowered, a click will be heard as its claw engages. After the click is heard, pull up on the connector to confirm that it is securely connected.

      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  7

  7. 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 C33 inverter with converter assembly connector.

      HINT: 

      Refer to PROCEDURE - Step 15 [11/2015 - 12/2018] , or refer to PROCEDURE - Step 15 [12/2018 - 07/2020] , or refer to PROCEDURE - Step 2 [07/2020 - ]

    3. Measure the resistance according to the value(s) in the table below.
      GTY554332Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Inverter with Converter Assembly)

      Standard Resistance

      (C33)

      (C33)

      Tester Connection Condition Specified Condition
      C33-24 (GND1) - Body ground Power switch off Below 1 Ω
      C33-23 (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

      (C33)

      (C33)

      Tester Connection Condition Specified Condition
      C33-6 (+B) - Body ground Power switch on (IG) 11 to 14 V
      C33-5 (+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 C33 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 HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - HYBRID VEHICLE CONTROL ECU) 
    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 C33 inverter with converter assembly connector.
    3. Disconnect the A50 hybrid vehicle control ECU 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.
      GTY601474Courtesy 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)

      Standard Voltage

      (A50)

      (A50)

      Tester Connection Condition Specified Condition
      A50-14 (HMCL) - Body ground Power switch on (IG) Below 1 V
      A50-4 (HMCH) - Body ground Power switch on (IG) Below 1 V
      NOTE:

      Turning the power switch on (IG) with the hybrid vehicle control ECU 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)

      (C33, A50)

      (C33)

      (A50)

      Tester Connection Condition Specified Condition
      C33-19 (HMCL) - A50-14 (HMCL) Power switch off Below 1 Ω
      C33-20 (HMCH) - A50-4 (HMCH) Power switch off Below 1 Ω

      Standard Resistance (Check for Short)

      (C33, A50)

      (C33)

      (A50)

      Tester Connection Condition Specified Condition
      C33-19 (HMCL) or A50-14 (HMCL) - Body ground and other terminals Power switch off 10 kΩ or higher
      C33-20 (HMCH) or A50-4 (HMCH) - Body ground and other terminals Power switch off 10 kΩ or higher

      HINT: 

      As there might be an intermittent malfunction, inspect the following items even if the measured resistance is as specified.

      Check that each connector between the inverter with converter assembly and hybrid vehicle control ECU is not loose or disconnected.

    10. Reconnect the A50 hybrid vehicle control ECU connector.
    11. Reconnect the C33 inverter with converter assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. CHECK HYBRID VEHICLE CONTROL ECU 
    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 C33 inverter with converter assembly connector.
    3. Measure the resistance according to the value(s) in the table below.
      GTY540218Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU)      		 - -

      Standard Resistance

      (A50)

      (A50)

      Tester Connection Condition Specified Condition
      A50-14 (HMCL) -A50-4 (HMCH) Power switch off 110 to 130 Ω
    4. Reconnect the C33 inverter with converter assembly connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE INVERTER WITH CONVERTER ASSEMBLY. Refer to  REMOVAL [11/2015 - 12/2018]  , or refer to  REMOVAL [12/2018 - 07/2020]  , or refer to  REMOVAL [07/2020 -] 

    Result: 

    NG 

    REPLACE HYBRID VEHICLE CONTROL ECU. Refer to  REMOVAL [11/2015 - 12/2018]  , or refer to  REMOVAL [12/2018 - 08/2019]  , or refer to  REMOVAL [08/2019 - 07/2020]  , or refer to  REMOVAL [07/2020 -] 

  10. REPLACE FUSE (PCU FR) 
    1. Replace the PCU FR fuse.
      GTY573547Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly
      *2 PCU FR Fuse
    2. Turn the power switch on (READY).
    3. Check if there is an open circuit in the PCU FR fuse in the No. 1 engine room relay block and No. 1 junction block assembly.

      OK

      There is no open circuit in the PCU FR 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  11

  11. CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - PCU FR FUSE) 
    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 PCU FR fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Disconnect the C33 inverter with converter assembly connector.
    4. Measure the resistance according to the value(s) in the table below.
      GTY551688Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 1 Engine Room Relay Block and No. 1 Junction Block Assembly *2 PCU FR Fuse
      *a Front view of wire harness connector
      (to Inverter with Converter Assembly)      		 - -

      Standard Resistance (Check for Short)

      (C33)

      (C33)

      Tester Connection Condition Specified Condition
      C33-6 (+B), C33-5 (+B2) or 2 (PCU FR fuse terminal) - Body ground and other terminals Power switch off 10 kΩ or higher
    5. Reconnect the C33 inverter with converter assembly connector.
    6. Install the PCU FR fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  12

  12. REPLACE INVERTER WITH CONVERTER ASSEMBLY 

    HINT: 

    Refer to REMOVAL [11/2015 - 12/2018] , or refer to REMOVAL [12/2018 - 07/2020] , or refer to REMOVAL [07/2020 -]

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (PCU FR) 

  13. REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (PCU FR) 

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