HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A78-202

DTC Code DTC Name
P0A78-202 Drive Motor "A" Inverter Performance

DESCRIPTION

For a description of the inverter, Click here.

DTC No. INF Code DTC Detection Condition Trouble Area
P0A78 202 Malfunction (short circuit) in the motor inverter inside the inverter with converter assembly

  • Inverter with converter assembly

  • Hybrid vehicle motor assembly

  • Motor cable

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.

Note


  • DTC P0A78-202 is stored after any of DTCs P0A78-113, 284, 286, 287, 505 and 506 are stored. After troubleshooting and repairing DTC P0A78-202, be sure to troubleshoot all the other DTCs.

  • Depending on the conditions in which the vehicle is being operated when a short circuit occurs in the inverter with converter assembly, the hybrid vehicle transaxle assembly may be affected. As this DTC is stored if a short circuit occurs in the inverter with converter assembly, it is necessary to perform a road test to check the hybrid vehicle transaxle assembly. If problems are found, replace the malfunctioning parts.

  • After completing the repair, including the repair of previously output DTCs, drive the vehicle at a speed of approximately 40 km/h (25 mph) for 1 minute and check that DTC P0A90-251 (Drive Motor "A" Performance) is not output. If DTC P0A90-251 (Drive Motor "A" Performance) is output, replace the hybrid vehicle motor assembly.

Tech Tips

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


  1. With the vehicle engine stopped, the power switch on (READY) and park (P) selected, depress the accelerator pedal to start the engine.

  2. Perform a road test according to the freeze frame data and item "Vehicle Spd" for approximately 10 minutes.

PROCEDURE


  1. CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MG2)

    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. A01J95T

      Remove the inverter terminal cover from the inverter with converter assembly.

    3. Disconnect the generator cable and motor cable from the inverter with converter assembly.

    4. A01JC44E01
      Text in Illustration
      *1 Motor Cable
      *2 Shield Ground

      Check MG2 for an interphase short using a milliohmmeter.


      1. Using a milliohmmeter, measure the resistance according to the value(s) in the table below.

        Tech Tips

        If the MG2 temperature is high, the resistance will vary greatly from the specification. Therefore, measure the resistance at least 8 hours after the vehicle is stopped.

        Standard Resistance
        Tester Connection Switch Condition Specified Condition
        e1-1 (W) - e1-2 (U) Power switch off 152.6 to 169.0 mΩ
        e1-2 (U) - e1-3 (V) Power switch off 157.6 to 174.0 mΩ
        e1-3 (V) - e1-1 (W) Power switch off 151.6 to 168.0 mΩ

        Tech Tips

        To correct the variation of the measured resistance due to temperature, use the following formula to calculate the resistance at 20°C (68° F).


        • R20 = Rt / {1 + 0.00393 X (T - 20)}

        The calculation is based on the following:


        • R20: Resistance at 20°C (68° F) (mΩ)

        • Rt: Measured resistance (mΩ)

        • T: Temperature when the resistance is measured (° C)

    5. Using a megohmmeter set to 500 V, measure the resistance according to the value(s) in the table below.

      Note

      Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      e1-2 (U) - Body ground and shield ground Power switch off 100 MΩ or higher
      e1-3 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      e1-1 (W) - Body ground and shield ground Power switch off 100 MΩ or higher

    6. Connect the generator cable and motor cable.

    7. Install the inverter terminal cover.


    NG

    Click here

    OK

  2. REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS


    1. Refer to replace inverter with converter assembly parts Click here.


    NEXT

    CHECK DTC OUTPUT (HV) Click here

  3. CHECK MOTOR CABLE

    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. Remove the motor cable.

    3. A01JC5AE01
      Text in Illustration
      *1

      Motor Cable

      (Inverter with Converter Assembly Side)
      *2 Shielded ground
      *3

      Motor Cable

      (Hybrid Vehicle Transaxle Assembly Side)

      Using a megohmmeter set to 500 V, measure the resistance according to the value(s) in the table below.

      Note

      Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      e1-2 (U) - Body ground and shield ground Power switch off 100 MΩ or higher
      e1-3 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      e1-1 (W) - Body ground and shield ground Power switch off 100 MΩ or higher

      Note

      Wrap the terminal of the three-phase AC cable with insulating tape to prevent them from coming into contact with body ground

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      e1-2 (U) - e2-3 (U) Power switch off Below 1 Ω
      e1-3 (V) - e2-2 (V) Power switch off Below 1 Ω
      e1-1 (W) - e2-1 (W) Power switch off Below 1 Ω
      e1-2 (U) - e2-2 (V) Power switch off 100 MΩ or higher
      e1-3 (V) - e2-1 (W) Power switch off 100 MΩ or higher
      e1-1 (W) - e2-3 (U) Power switch off 100 MΩ or higher

    5. Install the motor cable.


    NG

    CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MG2) Click here

    OK

  4. REPLACE HYBRID VEHICLE MOTOR ASSEMBLY


    1. Replace the hybrid vehicle motor assembly Click here.


    NEXT

  5. REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS


    1. Refer to replace inverter with converter assembly parts Click here.


    NEXT

    CHECK DTC OUTPUT (HV) Click here

  6. CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MG2)

    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 motor cable from the hybrid vehicle transaxle assembly.

    3. A01J9NGE01
      Text in Illustration
      *1 Hybrid Vehicle Transaxle Assembly

      Check MG2 for an interphase short using a milliohmmeter.


      1. Using a milliohmmeter, measure the resistance according to the value(s) in the table below.

        Tech Tips

        If the MG2 temperature is high, the resistance will vary greatly from the specification. Therefore, measure the resistance at least 8 hours after the vehicle is stopped.

        Standard Resistance
        Tester Connection Switch Condition Specified Condition
        e2-3 (U) - e2-2 (V) Power switch off 154 to 170 mΩ
        e2-2 (V) - e2-1 (W) Power switch off 148 to 164 mΩ
        e2-1 (W) - e2-3 (U) Power switch off 149 to 165 mΩ

        Tech Tips

        To correct the variation of the measured resistance due to temperature, use the following formula to calculate the resistance at 20°C (68° F).


        • R20 = Rt / {1 + 0.00393 X (T - 20)}

        The calculation is based on the following:


        • R20: Resistance at 20°C (68° F) (mΩ)

        • Rt: Measured resistance (mΩ)

        • T: Temperature when the resistance is measured (° C)

    4. Using a megohmmeter set to 500 V, measure the resistance according to the value(s) in the table below.

      Note

      Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V can result in damage to the component being inspected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      e2-3 (U) - Body ground and shield ground Power switch off 100 MΩ or higher
      e2-2 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      e2-1 (W) - Body ground and shield ground Power switch off 100 MΩ or higher

    5. Connect the motor cable.


    NG

    REPLACE MOTOR CABLE Click here

    OK

  7. REPLACE MOTOR CABLE


    1. Replace the motor cable Click here.


    NEXT

  8. REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS


    1. Refer to replace inverter with converter assembly parts Click here.


    NEXT

    CHECK DTC OUTPUT (HV) Click here

  9. REPLACE MOTOR CABLE


    1. Replace the motor cable Click here.


    NEXT

  10. REPLACE HYBRID VEHICLE MOTOR ASSEMBLY


    1. Replace the hybrid vehicle motor assembly Click here.


    NEXT

  11. REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS


    1. Refer to replace inverter with converter assembly parts Click here.


    NEXT

  12. CHECK DTC OUTPUT (HV)


    1. Check the other DTCs that were output together with DTC P0A78-202.

      Result
      DTC No. Relevant Diagnosis
      P0A78-113, 284, 286, 287, 505, 506 Drive Motor "A" Inverter Performance

      Note

      DTC P0A78-202 is stored after any of DTCs P0A78-113, 284, 286, 287, 505 and 506 are stored. After troubleshooting and repairing DTC P0A78-202, be sure to troubleshoot all the other DTCs.


    NEXT

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