2013 Corolla Motor Noise

[C1]

Went out to the garage this evening and noticed a really low level buzz type sound. At first thought it might be the smart meter, but finally caught it coming from the rear of the wife's 2013 Toyota Corolla. The car had not been driven anywhere for over nine hours. It had been just sitting there all along by itself in a dark garage (undisturbed, no key in the ignition). The sound was quite elusive; sounded like a small electric motor. Got out my medical stethoscope and got the best vibration of the sound off the gas tank; from rear underside of the car. (This also verified that it was the Corolla that was producing the sound.)

Just as I began listening to the gas tank with the stethoscope, the sound cut off. How long whatever it was that was running is unknown and I had not noticed the issue anytime before, but will keep an ear open in the future.

A guess is that it was a fuel pump in the rear tank (might even be something fancy related to fuel tank vapor control).

Does anybody know what the phenomena is? I cant find anything about this on the networks, but will ask the dealer also.

 

[fr]

Did it stop within 10 minutes? Did you try to turn the engine on and off?

 

[phucheneh]

A buzz would be the fuel pump motor. If it was evap stuff, you'd be hearing clicks.

If the car is off, you should be hearing nothing. How long did this noise last? You can pull fuses until it goes away (if it comes back) to determine which part is it. I would find the fuel pump fuse and relay first (underhood fusebox).

More than anything, you just need to try and find out what circumstances are replicating this. Then take it to the dealer; it's their job to fix odd behavior in brand new cars. The caveat is that you need to actually be able to tell them how to make it do the thing you're complaining about...vague descriptions are going to lead to 'no fault found' diagnoses.

 

[exar333]

Bees?

 

[Pulsar]

It's the hamster. Oil his wheel.

 

[LTC8K6]

Is it push button start?

Did you have the key fob on you?

Maybe it primed when you got near it?

 

[C1]

The auto was parked, unattended and unused for at least six hours. No key in the ignition. Nobody could have messed with it as it was in the garage.

How long the sound was being generated is unknown as I only noticed it inadvertently.

The electrical motor noise lasted a good five minutes, enough time for me to go in the house, get the key and open the trunk, check that it was not coming from rear speakers, go back into the house and get the stethoscope and monitor spots on the vehicle.

The sound stopped of its own when I was listening to the gas tank area which confirmed that the source was at or near there (ie, could actually pick up the vibrations thru the metal using the stethoscope).

After the sound stopped, I put the key in the ignition and turned it to accessory, but could not get the sound effect to reproduce/reoccur.

The questions are:

- What was running and for what purpose?
- Is this something that's supposed to happen or was something just stuck?
- If it is some kind of automation then where is it documented?

 

[LTC8K6]

Come to think of it, I remember learning on this board that some Toyotas apparently don't prime the way most cars do. That is, they don't prime when you turn the key on. They prime when the engine cranks, I think?

 

[fr]

My Prius does an evap system check that takes 10 minutes, starting exactly 5 hours after the car has been turned off.

The first time I noticed it, I was just walking through the garage and noticed a slow fan-like noise from the back of the you like you did. It is briefly mentioned in my manual as an "unconventional noise."

I have not heard of a Corolla doing it yet.

 

[phucheneh]

While it's certainly possible that there is a pump for evap, I can't recall ever seeing one on a Japanese car. I could understand having it on the Prius, or any other hybrid; but I dunno why they would add that expense to regular car with a naturally-aspirated engine. Intake vacuum makes for a perfectly acceptable 'leak detection pump.'

Although it is worth noting that Japanese cars are also somewhat infamous for their vague, hard-to-troubleshoot evap problems. I know Toyotas always liked to set P0441 for freakin' everything.

edit to clarify: not calling the above person a liar or anything...I don't doubt that his car a pump; just saying I've never done any evap work on a hybrid, but have on lots of standard 4cyl Hondas and Toyotas. Generally late 90's and early 2000's. Those systems were sometimes REALLY overcomplicated, in addition to the vague diagnostics.

If you want a laugh, look at the evap parts diagram for a mid-late 90's Nissan 'hardbody' type truck.

 

[7window]

The auto was parked, unattended and unused for at least six hours. No key in the ignition. Nobody could have messed with it as it was in the garage.

How long the sound was being generated is unknown as I only noticed it inadvertently.

The electrical motor noise lasted a good five minutes, enough time for me to go in the house, get the key and open the trunk, check that it was not coming from rear speakers, go back into the house and get the stethoscope and monitor spots on the vehicle.

The sound stopped of its own when I was listening to the gas tank area which confirmed that the source was at or near there (ie, could actually pick up the vibrations thru the metal using the stethoscope).

After the sound stopped, I put the key in the ignition and turned it to accessory, but could not get the sound effect to reproduce/reoccur.

The questions are:

- What was running and for what purpose?
- Is this something that's supposed to happen or was something just stuck?
- If it is some kind of automation then where is it documented?

Why waste your energy analyzing. You found the source of noise take it to the dealer since your car is 2013. Let them worry about it. Ask them if such noise is normal. We have the same car and never heard that noise but I won't worry because if the car is running right then its working. However I will bring it up to the dealer for documentation.

 

[pickerie]

I found the same issue.

Plan to have Toyota service explain this issue--correct if required.

This may have had to do with our battery dying a few months ago after work?

Toyota's reply better be good--I can't think of any reason why the fuel pump needs to run on a car that is < 12 months old after the car was driven in dry, 45 degree weather, then parked for ~2.5 hours on level garage floor.

Why would the computer need to increase fuel line pressure if there is no fuel consumption on a parked car? One thought is that the computer senses low fuel line pressure, then activates to increase to fuel pressure off level. Could mean that the computer firmware is not correctly programmed NOT to activate fuel pump if car key if in off position. Sounds like a 2013 Corolla on-board computer firmware bug.

Will update with Toyota service response.

 

[Doppel]

It is not an issue; nothing is wrong with your car. The prius is the first time I heard this, but I've heard it also on a Sienna. Several hours after the vehicle is stopped the car runs a test of some sort. It's very weird, but very normal.

Link--and yes this is to Prius but I'm almost positive I heard this on a Sienna as well: http://priuschat.com/threads/fuel-pump-running-when-car-is-powered-off.121811/

Yep, I did, here it is about Sienna: http://www.siennachat.com/forum/89-...0-humming-noise-underneath-when-parked-2.html

And, here we go, on the corolla: http://boards.straightdope.com/sdmb/showthread.php?t=500813

 

[leper84]

Car has a pump hooked in to the evaporative emissions system that lets it check for leaks. Most cars don't have them, just a different way about doing the same thing.