HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A0814

DTC Code DTC Name
P0A0814 DC/DC Converter Status Circuit Short to Ground or Open

DESCRIPTION

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

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 hybrid vehicle control ECU assembly 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
P0A0814 DC/DC Converter Status Circuit Short to Ground or Open

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

  • Hybrid vehicle control ECU assembly

 Does not come on

Master Warning Light:

Comes on

WIRING DIAGRAM

B004SCOE48
*1 ADC
*2 Inverter with Converter Assembly
*3 Hybrid Vehicle Control ECU Assembly

CAUTION / NOTICE / HINT

CAUTION:


  • B004STG

    Before the following operations are conducted, take precautions to prevent electric shock by turning the power switch off, wearing insulated gloves, and removing the service plug grip from HV battery.


    • Inspecting the high-voltage system

    • Disconnecting the low voltage connector of the inverter with converter assembly

    • Disconnecting the low voltage connector of the HV battery

  • B004Y5N

    To prevent electric shock, make sure to remove the service plug grip to cut off the high voltage circuit before servicing the vehicle.

  • B004SX1

    After removing the service plug grip from the HV battery, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.

  • B004W3JC06
    *a Without waiting for 10 minutes

    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.

Click here

CONFIRMATION DRIVING PATTERN

Tech Tips

After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

Click here


  1. Connect the GTS to the DLC3.

  2. Turn the power switch on (IG) and turn the GTS on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

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

  5. Turn the power switch on (IG) and turn the GTS on.

  6. With power switch on (IG) and wait for 10 seconds or more.

  7. Enter the following menus: Powertrain / Hybrid Control / Utility / All Readiness.

  8. Check the DTC judgment result.

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE, perform driving pattern again.

PROCEDURE


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

    Result
    Proceed to
    OK
    NG

    1. B004W01C01
      *A for LHD
      *B for RHD

      Check the connector connections and contact pressure of the relevant terminals for the hybrid vehicle control ECU assembly connectors.

      Click here

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

      Click here

      B004SKUC01
      *A for LHD *B for RHD

      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.
      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, 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.


    B

    CONNECT SECURELY

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

  3. CHECK HYBRID VEHICLE CONTROL ECU ASSEMBLY (CHECK WAVEFORM)


    1. Connect an oscilloscope between the hybrid vehicle control ECU assembly terminals specified in the table below.

    2. Turn the power switch on (IG).

    3. B004WNOC55
      *a

      Component with harness connected

      (Hybrid Vehicle Control ECU Assembly)

      Measure the waveform.

      Tester Connection Condition Equipment Setting
      A77-15 (VLO) - G92-6 (E1) Power switch on (IG) 5 V/DIV., 50 ms./DIV.
      OK
      The waveform appears as shown in the illustration.

      Tech Tips


      • Perform this inspection with the hybrid vehicle control ECU assembly 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 HYBRID VEHICLE CONTROL ECU ASSEMBLY) 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
      P0A0814 is not output. A
      P0A0814 is output again. B

    5. Turn the power switch off.


    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY Click here

  6. CHECK HARNESS AND CONNECTOR (RESISTANCE VALUE OF VLO INSIDE HYBRID VEHICLE CONTROL ECU ASSEMBLY)

    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 A79 inverter with converter assembly connector.

    3. B004X7OC52
      *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
      Tester Connection Condition Specified Condition
      A79-6 (VLO) - Body ground Power switch off 370 to 430 kΩ

    4. Reconnect the A79 inverter with converter assembly connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE INVERTER WITH CONVERTER ASSEMBLY Click here

    NG

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

    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 A79 inverter with converter assembly connector.

    3. Disconnect the A77 hybrid vehicle control ECU assembly connector.

    4. B004T9YC13
      *a

      Front view of wire harness connector

      (to Inverter with Converter Assembly)
      *b

      Rear view of wire harness connector

      (to Hybrid Vehicle Control ECU Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A79-6 (VLO) - A77-15 (VLO) Power switch off Below 1 Ω
      A79-6 (VLO) or A77-15 (VLO) - Body ground and other terminals Power switch off 10 kΩ or higher

    5. Reconnect the A77 hybrid vehicle control ECU assembly connector.

    6. Reconnect the A79 inverter with converter assembly connector.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE HYBRID VEHICLE CONTROL ECU ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR