DTC    P0A78-266    Drive Motor "A" Inverter Performance

DTC    P0A78-267    Drive Motor "A" Inverter Performance

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DESCRIPTION

The inverter converts high-voltage direct current from the HV battery and alternating current for the Motor and Generator. The inverter contains a three-phase bridge circuit, which consists of six power transistors each for the Motor and the Generator, that converts direct current to three-phase alternating current. The MG ECU controls the actuation of the power transistors. The inverter transmits information that is necessary for effecting control, such as the amperage and voltage, to the MG ECU.

A114848E01

The MG ECU uses a voltage sensor, which is built into the inverter, to detect boosted high voltage for boost control.
The inverter voltage sensor outputs voltage that varies between 0 and 5 V in accordance with the changes in the high voltage. The higher the high-voltage, the higher the output voltage, and the lower the high-voltage, the lower the output voltage.
The MG ECU monitors the inverter voltage and detects a malfunction.

DTC No.
INF Code
DTC Detection Condition
Trouble Area
P0A78
266
Open or short to GND in the inverter voltage (VH) signal line
  1. w/ converter inverter assembly (MG ECU)
↑
267
Short to +B in the inverter voltage (VH) signal line
  1. w/ converter inverter assembly (MG ECU)

MONITOR DESCRIPTION

The MG ECU monitors the inverter voltage (VH) sensor circuit. If the MG ECU detects an open or short malfunction of the VH sensor 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