Toyota Camry Hybrid - Engine Start?

depending on how the computer figures how much power it needs to move you the way you want to like for example you live in a hilly place and you leave your house and you have to negotiate an uphill climb, the computer knows that the motor generator alone cannot make that climb, so it will start up the engine in this case. or if the state of charge of the hybrid battery is a little low, the computer will likewise start the engine to help it charge up. there are a lot of variables that go into play with how these things work the way they do. but if you really feel real uneasy about it, bring it to a dealership to be looked at for your peace of mind.