Condition Inside the Hybrid Inverter Assembly is an Intelligent Power Module (IPM) which contains a control board
equipped with transistors. Due to software programming in the involved vehicles, certain transistors in the IPM could become damaged when operating the vehicle under high-load driving conditions, such as accelerating during highway driving. Codes P0A94, P324E, P3004 and P0A1A can also be stored in the ECU.
If this occurs, various warning lamps on the instrument panel will illuminate. In most cases the vehicle will enter a fail-safe mode, resulting in reduced motive power in which the vehicle can still be driven for short distances. In limited instances, the motor/generator ECU could reset, causing the hybrid system to shut down, resulting in the vehicle stopping while being driven and increasing the risk of a crash.
Remedy
Toyota dealers will perform a software update to the Motor Generator ECU and Power Management ECU at NO CHARGE to the vehicle owner. Additionally, if the vehicle has the condition present the inverter assembly will be replaced prior to the software updates. Toyota has completed remedy preparations and will begin to notify owners in Late February, 2014.