DTC    P0A78-306    Drive Motor "A" Inverter Performance

for Preparation Click here


DESCRIPTION

Refer to the description of the inverter. (Click here)
The MG ECU controls Motor torque according to driving conditions.

DTC No.
INF Code
DTC Detection Condition
Trouble Area
P0A78
306
Malfunction in monitoring Motor torque performance
  1. Hybrid vehicle transaxle assembly
  2. w/ converter inverter assembly (MG ECU)

MONITOR DESCRIPTION

If the difference between the requested MG2 torque and the actual MG2 torque exceeds a predetermined value, the HV control ECU determines that there is malfunction in the execution or monitoring of the MG2 torque. Then, the HV control ECU illuminates the MIL and sets a DTC.

INSPECTION PROCEDURE

CAUTION:
  1. Before inspecting the high-voltage system, take safety precautions to prevent electrical shocks, such as wearing insulated gloves and removing the service plug grip. After removing the service plug grip, put it in your pocket to prevent other technicians from reconnecting it while you are working on the high-voltage system.
  2. After disconnecting the service plug grip, wait for at least 5 minutes before touching any of the high-voltage connectors or terminals.

HINT:
At least 5 minutes is required to discharge the high-voltage capacitor inside the w/ converter inverter assembly.

1.READ OUTPUT DTC (HV)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to the ON position.

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

  1. Read output DTCs. (Click here)

    Result:
    The DTC shown in the table below is output:

    DTC No.
    		Relevant Diagnosis
    P0A1A (all details), P0A1B (all details), P0A1C (all details)
    		MG ECU circuit malfunction
    P0A1D (all details)
    		HV ECU circuit malfunction
    P0A3F (all details), P0A40 (all details), P0A41 (all details)
    		Motor resolver circuit malfunction
    P0A45 (all details), P0A46 (all details), P0A47 (all details)
    		Rear motor resolver circuit malfunction
    P0A4B (all details), P0A4C (all details), P0A4D (all details)
    		Generator resolver circuit malfunction
    P0A51 (all details), P0A55 (all details)
    		MG ECU circuit malfunction
    P0A60 (all details), P0A63 (all details)
    		Motor current sensor circuit
    P0A69 (all details), P0A6C (all details)
    		Rear motor current sensor circuit
    P0A72 (all details), P0A75 (all details)
    		Generator current sensor circuit
    P0A78-510, 508, 586, 266, 272, 280, 304, 267, 278, 283, 285, 305, 523
    		Motor inverter function malfunction
    P0A79-703, 701, 672, 690, 691, 697, 698
    		Rear motor inverter function malfunction
    P0A7A-522, 520, 309, 321, 323, 342, 343
    		Generator inverter function malfunction
    P0A94-585, 587, 561, 551, 588, 589, 545, 546, 552, 558, 559, 583, 584, 590
    		Boost converter circuit
    P0AA6 (all details)
    		High-voltage system insulation malfunction
    P3004-132
    		High-voltage system
    P3232-749, P3233-750
    		HV gate shutdown wiring malfunction

    HINT:
    1. Turning the ignition switch to the ON position with the service plug grip and inverter cover removed causes interlock switch system DTC P0A0D-350 to be output.
    2. P0A78-306 may be output due to a malfunction which causes the DTCs in the table above to be output. In this case, first troubleshoot the output DTCs in the table above. Then, perform a reproduction test to check that no DTCs are output.



YES
GO TO DTC CHART
NO


2.CHECK CONNECTION CONDITION OF MG ECU CONNECTOR (LOOSENESS AND POOR CONTACT)

CAUTION:
Be sure to wear insulated gloves.



    A103665E01

  1. Turn the ignition switch off and remove the service plug grip. (Click here)

    NOTICE:
    Do not put the vehicle into the READY-on state with the service plug grip removed as this may cause a malfunction.

  1. Remove the inverter cover. (Click here)

    NOTICE:
    1. Wrap the interlock round terminal for the inverter cover with vinyl tape to prevent it from shorting to ground.
    2. Prevent water in the reservoir tank from entering the inverter.
    3. Removing the inverter cover causes the MG ECU board to be exposed. Therefore, temporarily install the inverter cover for each area to be inspected.

  1. Check the connections of the MG ECU connectors.

    OK:
    Connectors are connected securely and there is no poor connection.



NG
CONNECT SECURELY
OK


3.CHECK W/ CONVERTER INVERTER ASSEMBLY (MOTOR)

CAUTION:
Be sure to wear insulated gloves.

  1. Check that the service plug grip is removed.



    A105180

  1. Check that the bolts for the three-phase AC cable for Motor are tightened to the specified torque.

Torque:
10 N*m{ 102 kgf*cm , 7 ft.*lbf }



NG
TIGHTEN THEM TO SPECIFIED TORQUE
OK


4.INSPECT HYBRID VEHICLE TRANSAXLE ASSEMBLY (MOTOR)

CAUTION:
Be sure to wear insulated gloves.

  1. Check that the service plug grip is removed.



    A111754E02

  1. Disconnect the three-phase AC cable of the HV Motor from the w/ converter inverter assembly.



    A111755E02

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

    Standard Resistance:
    Tester Connection
    		Specified Condition
    U - V
    		48 to 59 mΩ (20°C)
    V - W
    		48 to 59 mΩ (20°C)
    W - U
    		48 to 59 mΩ (20°C)

    NOTICE:
    If the Motor temperature is too high, the resistance changes greatly. Therefore, measure the resistance at least 8 hours after the vehicle is stopped.

  1. To correct the resistance varying depending on the temperature, use the following formula to calculate the resistance at 20°C.

    HINT:
    1. R20 = Rt / {1 + 0.00393 X (T - 20)}
    2. R20: Resistance at 20 °C (mΩ)
    3. Rt: Measured resistance (mΩ)
    4. T: Temperature when the resistance is measured (°C)

  1. Calculate the difference between the maximum and minimum resistance.

    Standard resistance:
    Difference is 5 mΩ or less

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

    Standard Resistance:
    Tester Connection
    		Specified Condition
    Three-phase AC Cable for Motor U terminal - Body ground and Shielded wire ground
    		10 MΩ or higher
    Three-phase AC Cable for Motor V termina - Body ground and Shielded wire ground
    		10 MΩ or higher
    Three-phase AC Cable for Motor W termina - Body ground and Shielded wire ground
    		10 MΩ or higher



NG
REPLACE HYBRID VEHICLE TRANSAXLE ASSEMBLY
OK

REPLACE W/ CONVERTER INVERTER ASSEMBLY