DTC    P0A78-272    Drive Motor "A" Inverter Performance

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DESCRIPTION

The inverter switches the power transistor on and off based on a driving signal sent from the MG ECU, in order to change the direction of the current that flows into the Generator. The inverter also regulates the duration of the switching time through PWM (Pulse Width Modulation) control, in order to control the voltage applied to the Generator.

DTC No.
INF Code
DTC Detection Condition
Trouble Area
P0A78
272
Abnormality in the motor PWM circuit
  1. w/ converter inverter assembly (MG ECU)

MONITOR DESCRIPTION

The MG ECU monitors the motor PWM circuit. If there is an error in the power transistor actuation signals which are transmitted to the inverter, the MG ECU interprets this as a malfunction of the motor PWM circuit. 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.CHECK CONNECTION CONDITION OF MG ECU CONNECTOR (LOOSENESS AND POOR CONTACT)

CAUTION:
Be sure to wear insulated gloves.



    A103665E03

  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

REPLACE W/ CONVERTER INVERTER ASSEMBLY