DTC    P0A78-523    Drive Motor "A" Inverter Performance

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DESCRIPTION

Refer to the description of the inverter. (Click here)

DTC No.
INF Code
DTC Detection Condition
Trouble Area
P0A78
523
Inverter voltage (VH) sensor offset malfunction
  1. HV relay assembly
  2. w/ converter inverter assembly

HINT:
Turning the ignition switch off causes the voltage in the inverter to discharge. The inverter voltage is almost 0 V after discharge. The DTC will be stored if the inverter voltage is more than the specified value after discharge.


A111758E01


MONITOR DESCRIPTION

The HV control ECU monitors the inverter voltage (VH) sensor signal. If the HV control ECU detects a fault in the sensor signal, the HV control ECU interprets this as a VH sensor failure. The HV control ECU then 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 VALUE OF INTELLIGENT TESTER (VL AND VH)

  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 / Data List / VL and VH.

    Standard Voltage:

    ECU Data List
    		Specified Condition
    Pre-boost voltage (VL)
    		Below 50 V
    Post-boost voltage (VH)
    		Below 50 V



NG
REPLACE W/ CONVERTER INVERTER ASSEMBLY
OK


2.CHECK FREEZE FRAME DATA INFORMATION (PWR RESOURCE VB, VL AND VH)

  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 / Freeze frame data / Pwr Resource VB, VL and VH.

    OK:
    HV battery voltage (Pwr Resource VB), pre-boost voltage (VL), and post-boost voltage (VH) are almost equal. (The difference among them is within 55 V.)



YES
REPLACE HV RELAY ASSEMBLY
NO

REPLACE W/ CONVERTER INVERTER ASSEMBLY