HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A09-591

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

DESCRIPTION

The hybrid vehicle converter (DC/DC converter) controls output voltage (12 V) based on duty ratio signals sent from the hybrid vehicle control ECU.

DTC No. INF Code DTC Detection Condition Trouble Area
P0A09 591 Hybrid vehicle converter voltage switching (VLO) signal circuit malfunction (Open or short to GND)

  • Hybrid vehicle converter

  • Hybrid vehicle control ECU

  • Wire harness or connector

WIRING DIAGRAM

A01GXDQE07

INSPECTION PROCEDURE

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 disconnecting 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.

Tech Tips

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

PROCEDURE


  1. CHECK DTC OUTPUT (HV)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.

    4. Check if DTCs are output.

      Result
      Result Proceed to
      P0A09-591 only is output. A
      P0AE6-225 is also output. B

    B

    GO TO DTC CHART (P0AE6-225) Click here

    A

  2. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONTROL ECU CONNECTOR)


    1. Check the connections of the hybrid vehicle control ECU connectors.

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

    NG

    CONNECT SECURELY

    OK

  3. CHECK CONNECTOR CONNECTION CONDITION (NO. 2 BATTERY PACK WIRE CONNECTOR)


    1. A01H29WE02

      Check the connection of the No. 2 battery pack wire connector.

      OK
      The connector is connected securely and there are no contact problems.

      Tech Tips

      For the removal and installation procedures related to inspection of the connection of the No. 2 battery pack wire connector, Click here.


    NG

    CONNECT SECURELY

    OK

  4. CHECK HYBRID VEHICLE CONTROL ECU (CHECK WAVEFORM)


    1. A01GW5AE03

      Connect an oscilloscope to the No. 2 battery pack wire connector terminals specified in the table below, and measure the waveform.

      Item Contents
      Terminal nS1-12 (VLO) - nS1-9 (GND)
      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 No. 2 battery pack wire connected.

      • The waveform (duty) will vary depending on inspection conditions.


    NG

    CHECK HARNESS AND CONNECTOR (RESISTANCE VALUE INSIDE HYBRID VEHICLE CONTROL ECU) Click here

    OK

  5. CLEAR DTC


    1. Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.

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

    3. Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.

    4. Clear DTCs and freeze frame data.


    NEXT

  6. CHECK DTC OUTPUT (HV)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch on (IG).

    3. Select the following menu items: Powertrain / Hybrid Control / Trouble Codes.

    4. Check if DTCs are output.

      Result
      Result Proceed to
      DTC P0A09-591 is not output. A
      DTC P0A09-591 is output again. B

    B

    REPLACE HYBRID VEHICLE CONTROL ECU Click here

    A

  7. CHECK FOR INTERMITTENT PROBLEMS


    1. Check for intermittent problems Click here.


    NG

    REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA

    OK

    REPLACE HYBRID VEHICLE CONTROL ECU Click here

  8. CHECK HARNESS AND CONNECTOR (RESISTANCE VALUE INSIDE HYBRID VEHICLE CONTROL ECU)


    1. Turn the power switch off.

    2. A01H29WE02

      Disconnect the No. 2 battery pack wire connector.

    3. A01GXOME07

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

      Standard resistance
      Tester Connection Switch Condition Specified Condition
      nS1-12 (VLO) - Body ground Power switch off 370 to 430 kΩ

    NG

    CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 2 BATTERY PACK WIRE CONNECTOR) Click here

    OK

  9. CHECK CONNECTOR CONNECTION CONDITION (HYBRID VEHICLE CONVERTER CONNECTOR)

    CAUTION:

    Be sure to wear insulated gloves.


    1. Turn the power switch off.

    2. A01H1FE
      A01H1W0

      Remove the service plug grip Click here.

      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.

    3. Check the connection of the low voltage connector of the hybrid vehicle converter.

      OK
      The connector is connected securely and there are no contact problems.

    NG

    CONNECT SECURELY

    OK

  10. CHECK HARNESS AND CONNECTOR (NO. 2 BATTERY PACK WIRE CONNECTOR - HYBRID VEHICLE CONVERTER)

    CAUTION:

    Be sure to wear insulated gloves.


    1. A01GXEHE08

      Check that the service plug grip is not installed.

    2. Disconnect the low voltage connector from the hybrid vehicle converter.

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

      Standard resistance (Check for open)
      Tester Connection Switch Condition Specified Condition
      nS1-12 (VLO) - z82-11 (VLO) Power switch off Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Switch Condition Specified Condition
      nS1-12 (VLO) or z82-11 (VLO) - Body ground and other terminals Power switch off 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE HV CONVERTER Click here

  11. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 2 BATTERY PACK WIRE CONNECTOR)


    1. Disconnect connector A76 from the hybrid vehicle control ECU.

    2. A01H0VYE08

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

      Standard resistance (Check for open)
      Tester Connection Switch Condition Specified Condition
      A76-27 (VLO) - nS1-12 (VLO) Power switch off Below 1 Ω
      Standard resistance (Check for short)
      Tester Connection Switch Condition Specified Condition
      A76-27 (VLO) or nS1-12 (VLO) - Body ground and other terminals Power switch off 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE HYBRID VEHICLE CONTROL ECU Click here