A car with a malfunctioning knock sensor can be technically drivable. However, the vehicle will consume significantly more gas than usual. It's difficult to say how safe the car is. The drivability depends on how much the engine relies on the knock sensor. There's a good chance you'll have an engine failure. It's simply a matter of time. The simple answer is that the engine is not entirely safe. As a result, be aware of the P0332 code and act quickly to replace it. Otherwise, you might face long-term problems.