Shenon Abewardana

Hi, I own a Toyota Axio 2015 hybrid car. Recently I have noticed that time to time EV mode stops working. When this happens RPM meter always show value around 2-3, even when the accelerator is released & speed is less than 50 kmph. Also when I accelerate the car & release the accelerator, the RPM value suddenly increase to 2-3 & does not come back to 0 value. I have recently checked the hybrid battery and replaced the shells too and the scan doesn't show any errors too. What could be the issue?