Single click upon acceleration

If you want to try and isolate the location in the engine compartment, you could open the hood and listen while your wife pushes about half way down on the gas pedal. The engine will start and continue to run at about 1,500 RPM until you let off the gas.

 

Are you sure it isn't just the automatic door locks? Does it happen again, after coming to a stop and then accelerating again?

 

Possibly related, possibly not ... In my regular (not-vagon) Prius, I hear what sounds like about 3-4 faint clicks in rapid succession. That happens shortly after starting from a stop, in forward or reverse, typically about the time the speedometer reaches 4 mph. It sounds as if it's somewhere under the hood. What is it?

 

It's worth looking into so you know. When I bought my Prius I needed to learn what sounded normal. There are so many strange sounds. The one that gets me the most is the air conditioning running when first starting up without the ICE running. It's a little louder than I thought it should be.

The futuristic sound of the car slowly pulling away from a stop without the ice running is another one. My wife thought something was wrong there for sure.

Good luck on your hunt for answers. Did you try opening the hood and pushing on the gas pedal?

 

I just started having the same noise once on take off and once on stop. What did you find?

 

I don't have any noises in my car except when it switches on the gasoline engine....

Could be cv joints or tired ice electric interface.....

 

First off: how many miles. Someone will ask, so lets get that one out of the way.

I assume that you know about the "space sound" that these cars make when traveling at low speeds. It is supposed to warn pedestrians that the vehicle is moving slowly. Maybe your "Space Sound" is broken, and just makes a click sound?

Possibly a relay, but which one? Is there a box of relays with the cover loose enough to allow sound out?

Find an empty parking lot, and recreate the problem with the hood open. Then have someone walk along side the car, to try to pinpoint the location.

 

I had this. See if it makes the noise when pushing the car back and forwards when car is in park. I fixed the noise by putting moly grease on both cv axle splines where it enters the wheel bearing. Common issue on nissan leafs too.