HYBRID CONTROL SYSTEM, Diagnostic DTC:P0A78-202

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

DTC SUMMARY

MALFUNCTION DESCRIPTION

  1. Internal inverter malfunction:


    • Inverter with converter assembly internal circuit malfunction

  2. Hybrid vehicle transaxle assembly malfunction


    • Open or short circuit

    • Iron particles or damage from foreign objects

DESCRIPTION

For a description of the inverter Click here.

Tech Tips

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

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

MONITOR DESCRIPTION

The MG ECU monitors the motor inverter electric current. If the current exceeds the threshold for a specified period of time, the power management control ECU will illuminate the MIL and set a DTC.

MONITOR STRATEGY

Related DTCs P0A78 (INF 202): MFIV detection (Short circuit malfunction)
Required sensors / components Motor inverter
Frequency of operation Continuous
Duration TMC's intellectual property
MIL operation 1 driving cycle
Sequence of operation None

TYPICAL ENABLING CONDITIONS

The monitor will run whenever the following DTCs are not present TMC's intellectual property
Other conditions belong to TMC's intellectual property -

TYPICAL MALFUNCTION THRESHOLDS

TMC's intellectual property -

COMPONENT OPERATING RANGE

Power management control ECU DTC P0A78 (INF 202) is not detected

CONFIRMATION DRIVING PATTERN

A01I2AGE01

  1. Connect the Techstream to the DLC3.

  2. Turn the power switch on (IG) and turn the Techstream 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 30 seconds or more.

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

  6. Turn the power switch on (READY).

  7. With the shift lever in P, and engine stopped, depress the accelerator pedal to start the engine. [A]

    Tech Tips

    Check that there are no abnormalities (abnormal sounds, coolant leaks, DTC output, etc).

  8. Perform a road test according to the freeze frame data "Vehicle Spd" for approximately 10 minutes. [B]

  9. Enter the following menus: Powertrain / Hybrid Control / Trouble Codes. [C]

  10. Read the current DTCs.

    Tech Tips


    • If a current DTC is output, the system is malfunctioning.

    • If a current DTC is not output and want to confirm permanent DTC, perform the following procedure.

  11. Check that permanent DTCs are cleared.

  12. If the permanent DTCs are not cleared, perform a universal trip, and then check for permanent DTCs again.

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 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.

  • DTC P0A78-202 is stored after any of DTCs P0A78-113, 284, 286, 287, 505 and/or 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 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 and item "Vehicle Spd" for approximately 10 minutes.

PROCEDURE


  1. CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR (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. A01I4TT

      Remove the upper inverter cover (generator cable side) and upper inverter cover (motor cable side) from the inverter with converter assembly.

    3. A01I3AIE05
      Text in Illustration
      *1 Generator Cable
      *2 Motor Cable

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

    4. A01I62VE06
      Text in Illustration
      *1 Shield Ground
      *a

      Motor Cable

      (Inverter with Converter Assembly Side)

      Check 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 Switch Condition Specified Condition
        n1-1 (W) - n1-3 (U) Power switch off 71.4 to 81.0 mΩ
        n1-2 (V) - n1-1 (W) Power switch off 71.4 to 81.0 mΩ
        n1-3 (U) - n1-2 (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)

    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 insulation tape.

      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
        Front 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 Switch Condition Specified Condition
      n1-1 (W) - Body ground and shield ground Power switch off 100 MΩ or higher
      n1-2 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      n1-3 (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 Switch Condition Specified Condition
      n1-2 (V) - n1-3 (W) Power switch off Below 1 Ω
      n1-1 (U) - n1-2 (V) Power switch off Below 1 Ω

    8. Reconnect the generator cable and motor cable.

    9. Install the upper inverter cover (generator cable side) and upper inverter cover (motor cable side).


    NG

    Click here

    OK

  2. REPLACE INVERTER WITH CONVERTER ASSEMBLY

    Click here


    NEXT

  3. CHECK DTC OUTPUT (HYBRID CONTROL)


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

      Result
      Relevant DTC
      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/or 506 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

    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 Click here.

    3. A01I615E01
      Text in Illustration
      *1 Shield ground
      *a

      Motor Cable

      (Inverter with Converter Assembly Side)
      *b

      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
      n1-1 (W) - Body ground and shield ground Power switch off 100 MΩ or higher
      n1-2 (V) - Body ground and shield ground Power switch off 100 MΩ or higher
      n1-3 (U) - Body ground and shield ground Power switch off 100 MΩ or higher

      Note

      Wrap the terminal of the motor 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
      n1-1 (W) - n2-3 (W) Power switch off Below 1 Ω
      n1-2 (V) - n2-2 (V) Power switch off Below 1 Ω
      n1-3 (U) - n2-1 (U) Power switch off Below 1 Ω
      n1-1 (W) - n2-1 (U) Power switch off 100 MΩ or higher
      n1-2 (V) - n2-3 (W) Power switch off 100 MΩ or higher
      n1-3 (U) - n2-2 (V) Power switch off 100 MΩ or higher

    5. Install the motor cable.

      Result
      Result Proceed to
      OK (When Not Using the Engine Support Bridge) A
      OK (When Using the Engine Support Bridge) B
      NG C

    NG

    CHECK HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR (MG2)) Click here

    OK

  5. REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY

    Click here (When Not Using the Engine Support Bridge))

    Click here (When Using the Engine Support Bridge))


    NEXT

  6. REPLACE INVERTER WITH CONVERTER ASSEMBLY

    Click here


    NEXT

  7. CHECK DTC OUTPUT (HYBRID CONTROL)


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

      Result
      Relevant DTC
      P0A78-113, 284, 286, 287, 505, 506 Drive Motor "A" Inverter Performance

      Note

      DTC P0A78-202 is stored after any of DTCs P0A78-113, 128, 284, 286, 287, 505 and/or 506 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 (MOTOR (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. A01I4HGE01
      Text in Illustration
      *a

      Component without motor cable connected

      (Hybrid Vehicle Transaxle Assembly)

      Check 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 Switch Condition Specified Condition
        n2-1 (U) - n2-2 (V) Power switch off 69.5 to 76.5 mΩ
        n2-2 (V) - n2-3 (W) Power switch off 66.5 to 73.5 mΩ
        n2-3 (W) - n2-1 (U) Power switch off 66.5 to 73.5 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. 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 insulation tape.

      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
        Front 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.

    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
      n2-1 (U) - Body ground Power switch off 100 MΩ or higher
      n2-2 (V) - Body ground Power switch off 100 MΩ or higher
      n2-3 (W) - Body ground Power switch off 100 MΩ or higher

    6. 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 Switch Condition Specified Condition
      n2-2 (V) - n2-3 (W) Power switch off Below 1 Ω
      n2-1 (U) - n2-2 (V) Power switch off Below 1 Ω

    7. Reconnect the motor cable.


    NG

    REPLACE MOTOR CABLE Click here

    OK

  9. REPLACE MOTOR CABLE

    Click here


    NEXT

  10. REPLACE INVERTER WITH CONVERTER ASSEMBLY

    Click here


    NEXT

  11. CHECK DTC OUTPUT (HYBRID CONTROL)


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

      Result
      Relevant DTC
      P0A78-113, 284, 286, 287, 505, 506 Drive Motor "A" Inverter Performance

      Note

      DTC P0A78-202 is stored after any of DTCs P0A78-113, 128, 284, 286, 287, 505 and/or 506 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 (When Not Using the Engine Support Bridge))

    Click here (When Using the Engine Support Bridge))


    NEXT

  14. REPLACE INVERTER WITH CONVERTER ASSEMBLY

    Click here


    NEXT

  15. CHECK DTC OUTPUT (HYBRID CONTROL)


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

      Result
      Relevant DTC
      P0A78-113, 284, 286, 287, 505, 506 Drive Motor "A" Inverter Performance

      Note

      DTC P0A78-202 is stored after any of DTCs DTCs P0A78-113, 128, 284, 286, 287, 505 and/or 506 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