P0A78-304

DESCRIPTION

Refer to the description of the inverter. (Click here)
Upon receiving a motor gate shutdown signal from the MG ECU, the inverter forcibly stops the motor by turning off all power transistors that are actuating the motor.
The MG ECU monitors the motor gate shutdown signal line and detects a malfunction.

DTC No.	INF Code	DTC Detection Condition	Trouble Area
P0A78	304	Open or short to +B in the motor gate shutdown (MSDN) signal line	w/ converter inverter assembly (MG ECU)
↑	305	Short to GND in the motor gate shutdown (MSDN) signal line	w/ converter inverter assembly (MG ECU)

MONITOR DESCRIPTION

The MG ECU monitors the motor gate shutdown (MSDN) signal line. If the MG ECU detects an open or short malfunction of the MSDN signal 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. READ OUTPUT DTC (HV)

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch to the ON position.

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

4. Read output DTCs. (Click here)

   Result:

   The DTCs shown in the table below are output:

   DTC No.	Relevant Diagnosis
   P3232-749, P3233-750	HV gate shutdown wiring malfunction

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.

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.

2. 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.
      

3. 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