P0A78-510

L110 HYBRID VEHICLE CONTROL: HYBRID CONTROL SYSTEM: P0A78-510: Drive Motor "A" Inverter Performance

DTC P0A78-510 - Drive Motor "A" Inverter Performance

DESCRIPTION

The inverter converts high-voltage direct current from the HV battery and alternating current for MG2 and MG1. The inverter contains a three-phase bridge circuit, which consists of six power transistors each for MG2 and MG1, 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.





The MG ECU uses a voltage sensor, which is built into the inverter, to detect boosted high voltage to allow control of the voltage boost.
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 malfunctions.

Upon receiving a motor gate shutdown signal from the MG ECU, the inverter forcibly stops MG2 by turning off all power transistors that are actuating MG2.
The MG ECU monitors the motor gate shutdown signal line and detects malfunctions.





HINT:
- If DTC P0A78-510 is output, the hybrid system cannot be restarted until the DTC is cleared.
- If the malfunction is not reproduced, leave the vehicle for 1 minute with the shift lever in the N position in order to easily reproduce the malfunction.

MONITOR DESCRIPTION

The MG ECU monitors the current that flows in MG2. If the current flows in MG2 while the vehicle is stationary with the power switch on (IG) or the shift lever in the N position, the MG ECU will detect a malfunction. The hybrid vehicle control ECU will illuminate the MIL and set a DTC.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS





COMPONENT OPERATING RANGE





INSPECTION PROCEDURE
CAUTION:
- Before inspecting the high-voltage system or disconnecting the low voltage connector of the inverter with converter assembly, take safety precautions such as wearing insulated gloves and removing the service plug grip to prevent electrical shocks. After removing the service plug grip, put it in your pocket to prevent other technicians from accidentally reconnecting it while you are working on the high-voltage system.
- After disconnecting the service plug grip, wait for at least 10 minutes before touching any of the high-voltage connectors or terminals. After waiting, check the voltage at the inspection point in the inverter with converter assembly. The voltage should be 0 V before beginning work.
HINT: Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with converter assembly.

PROCEDURE

1. CHECK CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CONNECTOR)




(a) Check the connection of the low voltage connector of the inverter with converter assembly.
Result:
The connector is connected securely and there are no contact problems.
NG -- CONNECT SECURELY
OK -- REPLACE INVERTER WITH CONVERTER ASSEMBLY