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Noise after parking? [normal = fuel evap system] (merged thread) - SOLVED!

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292K views 250 replies 145 participants last post by  WaitforVizzini 
#1 ·
First post on this forumn. After 30 years of car ownership I recently purchased my first Subaru, a 2011 Forester 2.5X. Nice car, my wife loves it, only has about 1300 miles on it. I went into the garage last night to get something and heard a buzzing noise coming from the rear of the Forester. It had been sitting in the garage turned off for at least 4 hours. The noise kind of reminded me of when the antenna motor on another car I had did not shut off when the car was turned off because the switch had gone bad.

I popped open the rear hatch then lifted and removed the spare tire cover. The noise was coming from the upper left (as I faced the rear of the car) of the area around the spare tire. Right behind the rear passenger seat. There was a plastic cover over where the noise was coming from so I couldn't see what was there. There was room to stick my hand under the bottom of the cover, so I felt around to see if I could determine what was buzzing. But I had not luck. While I was poking around the noise stoppped. It had been making the noise as I walked in the garage. I don't know how long it had been running before I went to the garage but until it stopped, it was probably 3 -5 minutes that I heard it.

I started up the car and took it for a drive to make sure everything was OK. It started and ran fine. When I brought it back there was no noise. I checked it several hours later and there was no noise.

Anyone know what this might be? It was definitely a very consistent electric buzzing noise. I am first of all concerened because it happened and I don't know what it is. I am also concerend because if this continues, it could run the battery down and strand my wife.

My first thought is that might be where the electronic fuel pump might be but I have no idea why it would be running after the car had been turned off four more than 4 hours.

The car is an X model without many options. Allow wheels, auto dimming mirror. No heated seats or anything that should be active while the car is turned off.

I thought I'd try here rather than go to the dealer because it's not very convenient to get there.
 
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#3 ·
The area you were poking around could certainly be the location of the fuel pump and I suppose the relay (not sure of the precise location on a SH model) thats the area under the rear seat on an SG model. Maybe shine a flashlight in the area to see if that provides any benefit to determining whats under there.

I'd keep an eye (ear:lol:) on it after your next few drives. And as Steve suggests check the cap, it does need to be tight to prevent a CEL.
 
#5 ·
Pretty sure on the SH that the fuel pump is in fact on the drivers side of the car rather than passenger side in older models. It should be a bit to the left between the spare and rear seats, so it does sound to be the area your noise was coming from.

Try opening it up again and looking at that area while you have someone turn the key to on (this should cause the fuel pump to run and "prime" for a few seconds without actually starting the motor so you can hear a bit easier) and see if you get the same noise from the same area.
 
#6 ·
I appreciate the suggestions.

I tried the gas cap when my wife got home and it was tight.

The location decribed above sounds exactly where the noise was coming from. As I face the rear of the car, to the upper left hand corner, directly behind the drivers side of the rear passenger seat.

Last night when I thought it might be the fuel pump I tried the test mentioned above also. I turned the key to the on position but didn't hear the noise althought it took me a few seconds to get back to where the noise had been.

If it is the fuel pump what would be the explanation for it running four hours after the car was shut off?
 
#9 ·
After being parked in the garage for about 6 hours, I'm hearing a humming sound (almost like a small pump) coming from a covered area in the floor of the cargo area on the driver side just ahead of the spare tire well (upper left of spare tire area when looking in the back). It went out after a few minutes.

Anybody know if this is expected behavior? Is it just re-pressurizing the fuel tank for emissions control? Is it going to keep doing this off and on and drain the battery if I leave it parked somewhere for a couple weeks?
 
#11 ·
Maybe it's humming because it has a song stuck in its head, but can't remember the words.

Does this car have the self-leveling suspension? My dealer said mine does (2011 XT) but I can't find any documentation to support it. I wonder because the last car I drove that did something similar had a pump that would try to keep the pressure up on a leaking self-leveling suspension.
 
#12 ·
A week ago I heard a humming near the rear left wheel area as well. It was a new week-old basic 2011 2.5X model and parked in the garage.

The best I can describe is that it sounds like a little electric motor humming. At the time I assumed it must have been a fuel pump keeping the pressure up. I have no idea what it could be.

I am very interested in hearing what it could be too.
 
#13 ·
Another word to describe it is a faint buzzing.

I found it in the manual at the very end of the brain-dead-litigious-warning section. It is related to emissions control with the fuel tank as I suspected.


General Information
  • Noise from under the vehicle
NOTE
You may hear a noise from under the vehicle approximately 5 hours after the engine is turned off. However, this does not indicate a malfunction. This noise is caused by the operation of the fuel evaporation leakage checking system and the operation is normal. The noise will stop after approximately 15 minutes.
 
#14 ·
Video with Sound ... BTW...Hi Everyone!

I just took this video to show the "problem"... luckily, I read page 9 after seeing SubaruForester . org responses...THANKS GUYS!
youtube DOT com/watch?v=-w5PJyW2Jfw

Sorry for the link this way ...I'm not a spammer but forum rules / software won't let me post full and correct link, and I think it may be interesting to many...
 
#15 · (Edited)
That's exactly what happened the other day to my 2011 2.5X Forester!

Thanks Porkpie for the information. First the ABS reset and now this evaporative leak check. Man I wish there was a quick reference guide to all these weird things. They don't bother me once I know what they are. As long as my Forester lasts without any engine or transmission problems past 100,000 miles then I'll be sold on Subaru for sure. I've given up on Ford, Dodge, and Kia for transmission problems. I'm gun shy now when it comes to a new vehicle.
 
#16 · (Edited)
Noise heard from rear under side when car is off

Several hours after turning off my 2012 Forester, I still heard a high pitched humming noise sound, almost like a fan or motor, coming from my rear undercarriage.
I heard this by putting my ears up in the rear wheel well.
I started and stopped the car and the sound stopped.
What can this sound be?
It was definately coming from the rear and not up near the engine.
I've read of fuel pump problems with past Subarus.
 
#17 · (Edited)
This is normal operation of the fuel evaporation leakage checking system

Turns out this is normal and not a malfunction.
- see page 9 of owners manual

Noise from under the vehicle
NOTE
You may hear a noise from under the vehicle approximately 5 hours after the
engine is turned off. However, this does not indicate a malfunction. This noise
is caused by the operation of the fuel evaporation leakage checking system
and the operation is normal. The noise will stop after approximately 15 minutes

See for what it sounds like.
 
#211 ·
This is normal operation of the fuel evaporation leakage checking system

Turns out this is normal and not a malfunction.
- see page 9 of owners manual

Noise from under the vehicle
NOTE
You may hear a noise from under the vehicle approximately 5 hours after the
engine is turned off. However, this does not indicate a malfunction. This noise
is caused by the operation of the fuel evaporation leakage checking system
and the operation is normal. The noise will stop after approximately 15 minutes

See for what it sounds like.
Thanks! 5hrs almost on the dot since I got home, and there it is. That explains why I usually hear it in the middle of the night.
 
#21 ·
Humming in the cargo area when off

Hello all
Odd intermittent problem here with my 2013 Forester. When the vehicle is off and I go out into the garage more often than not there is a humming sound coming from the rear of the car. I have pinpointed it to the cargo area behind the right rear seat and the spare tire. When I go out to the garage it sounds like a portable tire inflator running. It's been back to the dealership (its only 3 months old) and they say nothing is wrong.
Does anyone have any ideas as to what this may be? Possibly a relay staying on?

Any help/suggestions would be appreciated
 
#23 ·
It's the fuel evap leakage checking system - completely normal. Look here: http://www.subaruforester.org/vbulletin/f88/noise-heard-rear-under-side-when-car-off-107007/

From page 9 of owners manual:
Noise from under the vehicle
NOTE
You may hear a noise from under the vehicle approximately 5 hours after the
engine is turned off. However, this does not indicate a malfunction. This noise
is caused by the operation of the fuel evaporation leakage checking system
and the operation is normal. The noise will stop after approximately 15 minutes
 
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