HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A09-591

DTC Code DTC Name
P0A09-591 DC / DC Converter Status Circuit Low Input

DESCRIPTION

The DC/DC converter varies output voltage based on voltage change signals (VLO signal line) received from the power management control ECU.

If the vehicle is being driven with an inoperative DC/DC converter, the voltage of the auxiliary battery will drop, which will prevent the continued operation of the vehicle. Therefore, the power management control ECU monitors the operation of the DC/DC converter and alerts the driver if it detects a malfunction.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Warning Indicate
P0A09-591 DC / DC Converter Status Circuit Low Input

Open or short to ground in the signal line of DC/DC converter (VLO)

(1 trip detection logic)

  • Wire harness or connector

  • Inverter with converter assembly

  • Power management control ECU

 Does not come on

Master Warning Light:

Comes on

WIRING DIAGRAM

A00220AE04

CAUTION / NOTICE / HINT

CAUTION:


  • Before inspecting the high-voltage system or disconnecting the low voltage connector of the inverter with converter assembly, take safety precautions such as wearing insulated gloves and removing the service plug grip to prevent electrical shocks. After removing the service plug grip, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.

  • After removing the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting for 10 minutes, check the voltage at the terminals in the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.

    Click here

    Tech Tips

    Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

Note

After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

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Tech Tips

After the repair, clear the DTCs and perform the following procedure to check that DTCs are not output.


  1. Turn the power switch on (IG) and wait for 10 seconds or more.

PROCEDURE


  1. CHECK CONNECTOR CONNECTION CONDITION (POWER MANAGEMENT CONTROL ECU CONNECTOR)

    Result
    Proceed to
    OK
    NG

    1. Check the connector connections and contact pressure of the relevant terminals for the power management control ECU connectors.

      Click here

      OK
      The connectors are connected securely and there are no contact pressure problems.
      B003YJQC01
      *A for LHD *B for RHD
      Result
      Proceed to
      OK
      NG

    NG

    CONNECT SECURELY

    OK

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

    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

    CAUTION:

    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 manual because this may cause a malfunction.

    2. Check connection condition of the low voltage connector of the inverter with converter assembly and the contact pressure of each terminal. Check the terminals for deformation, and check the connector for water ingress and foreign matter.

      Click here

      A0020YPC01
      *A for LHD *B for RHD

      Note

      Before disconnecting the connector, confirm that it is properly connected by checking that the locking claws are engaged and that the connector does not pull out.

      OK
      - The connector is connected securely.
      - The terminals are not deformed and are connected securely.
      - No water or foreign matter in the connector.
      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

      Tech Tips

      When connecting the connector, insert it with the locking lever in the raised position. Rotate the lever downward and make sure that the connector is pulled into its socket. When the locking lever is in its fully closed position, a click will be heard as its locking claws engage. After the click is heard, pull up on the connector to confirm that it is properly connected.


    B

    CONNECT SECURELY

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

  3. CHECK POWER MANAGEMENT CONTROL ECU (CHECK WAVEFORM)


    1. Connect an oscilloscope between the power management control ECU terminals specified in the table below.

    2. Turn the power switch on (IG).

    3. A0020NPC11
      *a

      Component with harness connected

      (Power Management Control ECU)

      Measure the waveform.

      Item Content
      Terminal A62-14 (VLO) - K32-6 (E1)
      Equipment Setting 5 V/DIV., 50 ms./DIV.
      Condition Power switch on (IG)
      OK
      The waveform appears as shown in the illustration.

      Tech Tips


      • Perform this inspection with the power management control ECU connector connected.

      • The waveform varies depending on the specified DC/DC converter voltage.

    4. Turn the power switch off.

      Result
      Proceed to
      OK
      NG

    NG

    CHECK HARNESS AND CONNECTOR (RESISTANCE VALUE OF VLO INSIDE POWER MANAGEMENT CONTROL ECU) Click here

    OK

  4. CLEAR DTC

    Result
    Proceed to
    NEXT

    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

    4. Read and record the DTCs and freeze frame data.


      Powertrain > Hybrid Control > Trouble Codes

    5. Clear the DTCs and freeze frame data.


      Powertrain > Hybrid Control > Clear DTCs

    6. Turn the power switch off.

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK DTC OUTPUT (HYBRID CONTROL)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (READY).

    3. Enter the following menus: Powertrain / Hybrid Control / Trouble Codes.

    4. Check for DTCs.


      Powertrain > Hybrid Control > Trouble Codes
      Result
      Result Proceed to
      P0A09-591 is not output. A
      P0A09-591 is output again. B

    5. Turn the power switch off.


    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

  6. CHECK HARNESS AND CONNECTOR (RESISTANCE VALUE OF VLO INSIDE POWER MANAGEMENT CONTROL ECU)

    CAUTION:

    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 manual because this may cause a malfunction.

    2. Disconnect the A30*1 or A31*2 inverter with converter assembly connector.


      • *1: for LHD

      • *2: for RHD

    3. B003YFNC03
      *A for LHD
      *B for RHD
      *a

      Front view of wire harness connector

      (to Inverter with Converter Assembly)

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      A30-6 (VLO) - Body ground Power switch off 370 to 430 kΩ
      for RHD
      Tester Connection Condition Specified Condition
      A31-6 (VLO) - Body ground Power switch off 370 to 430 kΩ

    4. Reconnect the A30*1 or A31*2 inverter with converter assembly connector.


      • *1: for LHD

      • *2: for RHD

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE INVERTER WITH CONVERTER ASSEMBLY Click here

    NG

  7. CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - POWER MANAGEMENT CONTROL ECU)

    CAUTION:

    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 manual because this may cause a malfunction.

    2. Disconnect the A30*1 or A31*2 inverter with converter assembly connector.


      • *1: for LHD

      • *2: for RHD

    3. Disconnect the A62 power management control ECU connector.

    4. B003YL7C02
      *A for LHD
      *B for RHD
      *a

      Front view of wire harness connector

      (to Inverter with Converter Assembly)
      *b

      Rear view of wire harness connector

      (to Power Management Control ECU)

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      A30-6 (VLO) - A62-14 (VLO) Power switch off Below 1 Ω
      A30-6 (VLO) or A62-14 (VLO) - Body ground and other terminals Power switch off 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      A31-6 (VLO) - A62-14 (VLO) Power switch off Below 1 Ω
      A31-6 (VLO) or A62-14 (VLO) - Body ground and other terminals Power switch off 10 kΩ or higher

    5. Reconnect the A62 power management control ECU connector.

    6. Reconnect the A30*1 or A31*2 inverter with converter assembly connector.


      • *1: for LHD

      • *2: for RHD

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE POWER MANAGEMENT CONTROL ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR