I have noticed a couple of times in about a thirty minute period that my car buzzes when it's completely off. I noticed it yesterday when I was taking a nap in the back seats. I thought it was my phone but it was in do not disturb so that wasn't it. It happen twice yesterday, and again today: I just got in my car (parked and completely off) and I heard a little buzz. Almost like a phone notification when on vibrate mode.

Does anybody know what this is and if it's normal?

 

 

ghost?

 

lol better not be!
I heard it again. I get in the cart through one of the back doors so the car never turns on, not even in accessory mode. It's not a hissing noise, more like when your phone is on vibrate and you leave it on a hard surface and receive a notification. Short and not too loud but noticeable if you're quiet.

 

I wonder if it could have something to do the EVAP system in the fuel tank?

 

Good thought. There is a vacuum pump that checks the EVAP system for leaks. It operates when the vehicle is turned off.

 

Thank you guys! I will ask when I take it for maintenance. I won't worry much now.

 

^^ This is what it is. My Lexus does this after it sits awhile. Totally normal.

 

 

 

The RDX's EVAP system uses engine vacuum - not vacuum generated by a separate pump, so that can't be the source of the noise.

The only electrically-powered pumps I can think of are located in the:

- ABS/VSA modulator - generates hydraulic pressure to brake individual wheels for AHA, ACC, CMBS, VSA, etc.
- Rear differential unit - generates hydraulic pressure to apply the left and right clutches to apply torque to drive each rear wheel
- In-tank "low pressure" fuel pump - pumps fuel to the high-pressure fuel pump mounted on the engine
- Windshield washer fluid pump - self explanatory

There's no reason for any of these pumps to operate when the engine is off.

There are dozens of electric motors:

- Engine cooling fans (2)
- Starter
- Power windows (4)
- Power lock actuators (4)
- Sunroof (2)
- HVAC blower
- HVAC blend/mode doors (4)
- Turbocharger wastegate actuator
- Electric power steering
- Tailgate raise/lower
- Tailgate latch
- Power seats (10-14 depending on trim)
- Audio-navigation unit cooling fan
- Transmission parking mechanism