HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A78-202

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

DTC SUMMARY


  1. MALFUNCTION DESCRIPTION


      Internal inverter malfunction

    • Inverter with converter assembly internal circuit malfunction


      Hybrid vehicle transaxle assembly malfunction

    • Open or short circuit

    • Iron particles or damage from foreign objects

DESCRIPTION

For a description of the inverter.

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Tech Tips

The term "drive motor A" indicates the motor (MG2).

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Warning Indicate
P0A78-202 Drive Motor "A" Inverter Performance

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 (indicating 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

 Comes on

Master Warning Light:

Comes on

WIRING DIAGRAM

Refer to the wiring diagram for DTC P0AA6-526.

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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.

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    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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  • DTC P0A78-202 is stored after DTCs P0A78-113, 284, 286, 287, 505 and/or 506 are stored. After troubleshooting and repairing the malfunction which caused DTC P0A78-202 to be stored, 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 engine stopped, the power switch 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 item "Vehicle Spd" for approximately 10 minutes.

PROCEDURE


  1. CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR (MG2))

    Result
    Proceed to
    OK
    NG

    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. B002JCXC02
      *A for 2WD
      *B for AWD

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

    3. B002JW4C02
      *A for 2WD
      *B for AWD
      *1 Motor Cable

      Disconnect the motor cable from the inverter with converter assembly.

    4. B002JCBC41
      *1 Shield Ground
      *a

      Motor Cable

      (Inverter with Converter Assembly Side)

      Check the motor (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 Condition Specified Condition
        v1-1 (W) - v1-3 (U) Power switch off 71.4 to 81.0 mΩ
        v1-2 (V) - v1-1 (W) Power switch off 71.4 to 81.0 mΩ
        v1-3 (U) - v1-2 (V) Power switch off 74.4 to 84.1 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 (°F).)

    5. When checking for a short circuit between motor phases without using a milliohmmeter.

      Note

      The motor generates current when wheels are rotated by hand. Before performing the inspection, wrap the motor cable terminals with tape (non-residue type) or equivalent.

      Tech Tips

      A short circuit between the motor phases can be checked simply without using a milliohmmeter.


      1. Connect the cable to the negative (-) auxiliary battery terminal.

      2. Turn the power switch on (IG).

        Note

        Turning the power switch on (IG) with the service plug grip removed causes other DTCs to be stored. Clear the DTCs after performing this inspection.

      3. Move the shift lever to N.

      4. Lift up the vehicle.

      5. Rotate the front wheels in the same direction simultaneously by hand.

        Standard
        Left and right wheels rotate smoothly (No short circuit between phases)

        Tech Tips

        If a short circuit exists between the motor phases, the front wheels do not rotate smoothly (some resistance is felt).

      6. Lower the vehicle.

      7. Move the shift lever to P.

      8. Turn the power switch off.

      9. Disconnect the cable from the negative (-) auxiliary battery terminal.

    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 Condition Specified Condition
      v1-1 (W) - Body ground and shield ground Power switch off 100 MΩ or higher
      v1-2 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      v1-3 (U) - Body ground and shield ground Power switch off 100 MΩ or higher

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

      Tech Tips

      Perform this procedure only when checking for a short circuit between motor phases without using a milliohmmeter.

      Standard Resistance
      Tester Connection Condition Specified Condition
      v1-1 (W) - v1-2 (V) Power switch off Below 1 Ω
      v1-2 (V) - v1-3 (U) Power switch off Below 1 Ω

    8. Reconnect the motor cable.

    9. Install the inverter cover UPR.

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY Click here

    OK

  2. REPLACE INVERTER WITH CONVERTER ASSEMBLY

    Click here

    Result
    Proceed to
    NEXT

    NEXT

    GO TO STEP 5 Click here

  3. REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY

    Click here

    Result
    Proceed to
    NEXT

    NEXT

  4. REPLACE INVERTER WITH CONVERTER ASSEMBLY

    Click here

    Result
    Proceed to
    NEXT

    NEXT

  5. CHECK DTC OUTPUT (HYBRID CONTROL)


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


      Powertrain > Hybrid Control > Trouble Codes
      Result
      Relevant DTC
      P0A78-113, 284, 286, 287, 505, 506 Drive Motor "A" Inverter Performance

      Note

      DTC P0A78-202 is stored after DTCs P0A78-113, 128, 284, 286, 287, 505 and/or 506 are stored. After troubleshooting and repairing the malfunction which caused DTC P0A78-202 to be stored, be sure to troubleshoot all the other DTCs.

      Result
      Proceed to
      NEXT

    NEXT

    GO TO DTC CHART (HYBRID CONTROL SYSTEM) Click here