My 2012 Pruis v makes a humming noise

welcome to p/c! mine has a whistling noise sometimes. i figure it's from all the electrics.

 

Battery fan cycling on, high/low, off, perhaps?

 

There's a battery fan that pulls air from under the rear seat to cool the battery pack --
there's the electric brake pump - when you first open the driver door that generates the friction brake pressure....
that's driver side though -

There's the electric fuel pump under the car towards the rear (in tank) ... sometimes you can hear those ...whirring ...
but it would only do that while the ICE is running...and generally you don't hear them inside the car...only if you are standing outside next to it...

On mine - I hear the high frequency of the inverter from time to time - especially as I transition from gas to brake...

could be blower motor --
could be AC compressor...
power steering electric assist?

radio noise... especially if you have an amp installed...

there's a multitude of possibilities.

Also - after the car has been off for a bit - there is a pump that runs... and draws vacuum on the gas tank to check the intergrity of the gas cap seal, as well as the "purge canister" (correct me someone) ... which all has to do with emission control ... there is what's called an evap canister - that has charcoal in it - essentially captures fuel vapors from the tank vent - and i believe routes them back into the engine or exhaust to be burned off... and EPA requires that they monitor the function of the system. (it's like this on non-hybrids too) ... only my non-hybrid SUV does it while driving down the road - and uses engine vacuum to run the tests... that's why if you leave your gas cap loose or off - it will set a service engine light... provided it was that way when the vehicle computer performed its test.

 

Glad to hear others reporting humming/whistling. I localize mine to the "right front tire" area. I hear it most when pulling out of a parking spot - especially after a rainy night (I park outside on the street). It fades as the car starts driving. Thoughts?

 

The right side of the 1.8L engine also has the electric water pump. It only runs as needed to keep the engine temperature right. If you have a Scanguage or equivalent OBD scanner, see if the coolant temperature drops shortly after hearing the noise. That would confirm a noisy, engine water pump.

It could also be the cabin heater water pump. If the heat is on and the noise comes on, flip the heater off. If the noise goes away and comes back with heat turned on, it would confirm the diagnosis.

GOOD LUCK!
Bob Wilson

 

Are you referring to something more like a "woo, woo, woo" sound coming from the wheel, lasts about 200-300 feet down the road? May want to check out this thread that deals with an intermittent brake sound that many experience: 2012 Prius v Groaning Noise | PriusChat

 

ketch22 - thanks for checking in and for the link. It's not a "woo-woo-woo" sounds. It's more squeaky - after owning the car for several months, it seems to happen only after a rainy or dewy evening then restart in the morning, but it's there every restart after rest. It no longer bothers or concerns me. Hope that's wise!