Electric Motor Noise?

I can't say I've ever heard that noise before. How many miles on your car?

 

I would bring it to the dealer and have them look into it. It should be covered under warranty

Hybrid-Related Component Coverage

Hybrid-related components, including the HV battery, battery control module, hybrid control module and inverter with converter, are covered for 8 years/100,000 miles. The HV battery may have longer coverage under the Emissions Coverage. Refer to your Owner’s Warranty Information booklet for details.

 

weird noise. is this from the electric coolant pump going bad?

 

I suggest that you need to decide whether the noise is coming from:

- the inverter coolant pump (located behind the driver's headlight assembly);
- the coolant heat recovery pump (which is located in the driver's side front fender well, in front of the tire);
- the brake actuator pump (located on the firewall, hidden under the cowl tray that houses the windshield wiper motor);
- or some other area.

 

The inverter water pump is under there, which is a recall item from Toyota.

If you take the cap off the inverter reservoir, you should be able to see turbulence in the coolant when the car is on. If you don't see turbulence, the pump is not working.

 

"It sounds like it's coming from under the silver cover - what's under there?"
There are no mechanical moving parts under the silver inverter cover, only electronics.

I think it is likely that the brake actuator motor (mounted on the firewall) is the source of the noise. What warning lights are on?

 

You need one of these: Mechanic's Stethoscope

 

100% certain:
Coolant Control Valve, toyota part number 16670-21010 about $60
If it fully fails it will throw a p1121 code. Mine did the same thing, it would throw a code for a day then clear then do it again. Relatively easy repair, definitely buy cable operated hose clamp pliers. I used this thread when I swapped mine out:
P1121 - Coolant Control Valve Replacement (with pics) | PriusChat

 

That noise is the coolant control valve. Without a doubt. The reason they say it's not is because it hasn't thrown a code yet. P1121 when it finally fails. The battery issue is (if real) unrelated. They were correct about the noise being harmless as a failure of the valve isn't a critical failure. Typically it'll mean no or reduced cabin heat. But that noise is 100% the valve cycling back and forth as it tries to determine what position it's in. And FYI that is one of the best recordings of it I've heard.

 

Here is another user that had it and recorded the same noise (a different cadence but still the same). When mine failed it was more like yours (I bought it and it was making that noise, I didn't know it wasn't supposed to do that). Strange Reciprocating Noise Sound under hood EV mode Gen 2 prius | PriusChat. Edit: I drove with mine for around six months before it finally threw the p1121 code. Then it would clear.. Then come back on.. I had no drivability issues but had to fix it as a car cannot pass inspection in texas if the MIL is on regardless of reason.

 

No problem. This is one of things that can definitely wait. If you want to tackle it someday I'll be happy to help walk you through it, just pm me.

 

Did you document the abnormal noise in writing? This will come in handy when the code will show up after your warranty expires.