power steering failing

[yarispe]

In two occasions while parking the steering lost power momentarily. Then in one other occasion when stopped at a red light it happened again.
The mechanic says it's a battery problem and needs to be replaced.
My question is: Will I be able to steer the car manually if the power steering dies?
I wonder if without power steering the wheels might be locked.

BTW this is a Yaris 2008 with auto transmission.

[CTScott]

The power steering is just an assist, so you can still steer if it stops working.

The primary reason why it turns off is overheating. The Power Steering ECU gets hot as it drives the electric motor, and the more that you turn the wheel at low speed the hotter it gets. Once it reaches a specific temperature inside of the ECU it temporarily shuts off.

When yours cuts out does the PS light come on on the cluster?

[yarispe]

I noticed the PS light on once but can't say it didn't come on the other times as I wasn't paying attention.
They replaced the battery... and so far so good.