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

Current flowing to any of the phases exceeds a certain level after a DTC (indicates a motor inverter malfunction: overheating, overcurrent or circuit malfunction) is stored and the motor inverter is shutdown

(1 trip detection logic)

  • Inverter with converter assembly

  • Hybrid vehicle transaxle assembly

  • Motor cable

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 ignition 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.

  • DTC P0A78-202 is stored after any of DTCs P0A1B-505, P0A40-506, P0A78-113, 284, 286 and 287 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 transaxle 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 ignition switch to ON (READY) and the shift lever in P, 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 ignition switch to ON (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. A004EQ3

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

    3. A004G00

      Remove the inverter cover from the inverter with converter assembly.

    4. A004FPX

      Disconnect the motor cable from the inverter with converter assembly.

    5. A004EKZE01
      Text in Illustration
      *1 Shield Ground
      *a

      Motor Cable (for MG2)

      (Inverter with Converter Assembly Side)

      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
        W4-1 (W) - W4-2 (U) Ignition switch off 172.5 to 190.7 mΩ
        W4-2 (U) - W4-3 (V) Ignition switch off 172.5 to 190.7 mΩ
        W4-3 (V) - W4-1 (W) Ignition switch off 172.5 to 190.7 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)

    6. 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
      W4-1 (W) - Body ground and shield ground Ignition switch off 100 MΩ or higher
      W4-2 (U) - Body ground and shield ground Ignition switch off 100 MΩ or higher
      W4-3 (V) - Body ground and shield ground Ignition switch off 100 MΩ or higher

    7. Connect the motor cable.

    8. Install the inverter cover.

    9. Install the inverter terminal cover.


    NG

    CHECK MOTOR CABLE (FOR MG2) Click here

    OK

  2. REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS

    Click here


    NEXT

  3. CHECK DTC OUTPUT (HYBRID CONTROL)


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

      Result
      DTC No. Relevant Diagnosis
      P0A1B-505 Drive Motor "A" Control Module
      P0A40-506 Drive Motor "A" Position Sensor Circuit Range/ Performance
      P0A78-113, 284, 286, 287 Drive Motor "A" Inverter Performance

      Note

      DTC P0A78-202 is stored after any of DTCs P0A1B-505, P0A40-506, P0A78-113, 284, 286 and 287 are stored. After troubleshooting and repairing DTC P0A78-202, be sure to troubleshoot all the other DTCs.


    NEXT

    GO TO DTC CHART (HYBRID CONTROL SYSTEM) Click here

  4. CHECK MOTOR CABLE (FOR 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 ignition switch to ON (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Remove the motor cable Click here.

    3. A004EQ2E01
      Text in Illustration
      *1 Shield ground
      *a

      Motor Cable (for MG2)

      (Inverter with Converter Assembly Side)
      *b

      Motor Cable (for MG2)

      (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
      W4-1 (W) - Body ground and shield ground Ignition switch off 100 MΩ or higher
      W4-2 (U) - Body ground and shield ground Ignition switch off 100 MΩ or higher
      W4-3 (V) - Body ground and shield ground Ignition switch off 100 MΩ or higher

      Note

      Wrap the terminal of the motor cable (for MG2) 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
      W4-1 (W) - W3-1 (W) Ignition switch off Below 1 Ω
      W4-2 (U) - W3-3 (U) Ignition switch off Below 1 Ω
      W4-3 (V) - W3-2 (V) Ignition switch off Below 1 Ω
      W4-1 (W) - W3-3 (U) Ignition switch off 100 MΩ or higher
      W4-2 (U) - W3-2 (V) Ignition switch off 100 MΩ or higher
      W4-3 (V) - W3-1 (W) Ignition switch off 100 MΩ or higher

    5. Install the motor cable.


    NG

    CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MG2) Click here

    OK

  5. REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY

    Click here


    NEXT

  6. REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS

    Click here


    NEXT

  7. CHECK DTC OUTPUT (HYBRID CONTROL)


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

      Result
      DTC No. Relevant Diagnosis
      P0A1B-505 Drive Motor "A" Control Module
      P0A40-506 Drive Motor "A" Position Sensor Circuit Range/ Performance
      P0A78-113, 284, 286, 287 Drive Motor "A" Inverter Performance

      Note

      DTC P0A78-202 is stored after any of DTCs P0A1B-505, P0A40-506, P0A78-113, 284, 286 and 287 are stored. After troubleshooting and repairing DTC P0A78-202, be sure to troubleshoot all the other DTCs.


    NEXT

    GO TO DTC CHART (HYBRID CONTROL SYSTEM) Click here

  8. 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 ignition switch to ON (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Disconnect the motor cable (for MG2) from the hybrid vehicle transaxle assembly.

    3. A004EHCE02
      Text in Illustration
      *a

      Component without motor cable (for MG2) connected

      (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 motor (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
        W3-1 (W) - W3-3 (U) Ignition switch off 170.3 to 188.1 mΩ
        W3-2 (V) - W3-1 (W) Ignition switch off 170.3 to 188.1 mΩ
        W3-3 (U) - W3-2 (V) Ignition switch off 170.3 to 188.1 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
      W3-1 (W) - Body ground Ignition switch off 100 MΩ or higher
      W3-2 (V) - Body ground Ignition switch off 100 MΩ or higher
      W3-3 (U) - Body ground Ignition switch off 100 MΩ or higher

    5. Connect the motor cable (for MG2).


    NG

    REPLACE MOTOR CABLE Click here

    OK

  9. REPLACE MOTOR CABLE

    Click here


    NEXT

  10. REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS

    Click here


    NEXT

  11. CHECK DTC OUTPUT (HYBRID CONTROL)


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

      Result
      DTC No. Relevant Diagnosis
      P0A1B-505 Drive Motor "A" Control Module
      P0A40-506 Drive Motor "A" Position Sensor Circuit Range/ Performance
      P0A78-113, 284, 286, 287 Drive Motor "A" Inverter Performance

      Note

      DTC P0A78-202 is stored after any of DTCs P0A1B-505, P0A40-506, P0A78-113, 284, 286 and 287 are stored. After troubleshooting and repairing DTC P0A78-202, be sure to troubleshoot all the other DTCs.


    NEXT

    GO TO DTC CHART (HYBRID CONTROL SYSTEM) Click here

  12. REPLACE MOTOR CABLE

    Click here


    NEXT

  13. REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY

    Click here


    NEXT

  14. REFER TO REPLACE INVERTER WITH CONVERTER ASSEMBLY PARTS

    Click here


    NEXT

  15. CHECK DTC OUTPUT (HYBRID CONTROL)


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

      Result
      DTC No. Relevant Diagnosis
      P0A1B-505 Drive Motor "A" Control Module
      P0A40-506 Drive Motor "A" Position Sensor Circuit Range/ Performance
      P0A78-113, 284, 286, 287 Drive Motor "A" Inverter Performance

      Note

      DTC P0A78-202 is stored after any of DTCs P0A1B-505, P0A40-506, P0A78-113, 284, 286 and 287 are stored. After troubleshooting and repairing DTC P0A78-202, be sure to troubleshoot all the other DTCs.


    NEXT

    GO TO DTC CHART (HYBRID CONTROL SYSTEM) Click here