I ve had mine since December 19th and heard that the other day. i started it up, double checked the parking brake, shut off. Been ok since. Would like to know also.

 

I had the exact same thing happen. Went into the garage where the car had been parked for hours. Heard that sound and determined it was coming from the rear. Went to get my phone to record it, but it had stopped by the time I got back.

I have no idea how long it had been making that noise, but it was very odd that it was making it after having been parked for several hours.

 

The exact same thing happened to me the day after I bought my '17 CRV - I went out into the garage to turn on the outside garage light, and my car was making a buzzing/vibrating noise. I thought I was crazy because it stopped shortly thereafter and I've never heard it since. I'd love to find out what this is.

 

Thanks for this post. Has anyone been able to get any confirmation from Honda regarding this? I was unable to through dealer or Honda directly.

 

Part of the emissions testing on all cars is to check for fuel vapor leaks. There are many ways to do this, one of them is to seal the system and run a small vacuum pump and then use a pressure sensor to test for leaks. This has to be done well after the car is shut down and totally cooled off or else the natural pressure changes in the fuel tank will cause false readings. It is very likely you just happened to be in a quiet place when such a test occurred and you heard the pump back in the rear of the car that is used for the test. I will have to look into this further but that is a very common cause of this unexplained noise in that area.

Not to worry, nothing is wrong. Even my motorcycle does emissions tests after I turn it off. Its strange to hear it the first time, buzzes, clicks and noises from nowhere...

 

Thank You.

 

Mine was making this noise just tonight when I went out to the garage. Started the car up and turned it off and the noise stopped. Have the car two weeks and this is the first time I have heard it.

 

Its actually rare on most cars to be lucky enough to catch it. It only runs under certain conditions based on time and temperature in most cases. Back in the mid to late 1990's when cars first started with these OBD-II tests we got a lot of panicked owners bringing their cars in and a lot of dealer techs scratching their heads until we got them up to speed on what was happening. When I read the early posts on this I had to smile...we were dealing with this stuff twenty years back.

 

I had the same sound yesterday... So is it something that need to dealt with? Or safe to be ignored? How often will it reacurr?

 

I had the same sound in my 2015 CR-V. I attributed it to expansion of the gasoline vapor that was passed through the filtration of the fuel system thus no gasoline smell. This may be the same thing.

Now here is a question for those experiencing this. Are you bringing you CR-V in from the cold into a warmer garage? This might case the problem as the gasoline warms.

 

Yes is was from a cold outside to a warmer garage!

 

I've "caught" my '17 EX-l making this noise twice now. Both time after having been parked for some time.

 

Caught the noise also. Surprised how loud it was. Thanks Hans471 for the explanation.

 

I have owned several new car in the last 5 years and never had any noises as described. I spend alot of time in my garage because my main workshop is in there . For giggles I went to a Honda dealers parts list to find that system....nothing that would look like a pump or pressure device.
This is one of the areas that had a solenoid but no pump
https://www.cheaperhondaparts.com/a...y-trim/variable-engine/electrical-exhaust-heater-fuel-cat/air-bypass-valve-scat

 

Oops, I created a new thread on this. I had the same problem last night. Called the dealer's service department and asked them before I found the answer. They had no clue.

 

Just went in my garage and heard "the noise" for the first time since I've had my CR-V (February purchase, 2200 miles to date) and remembered reading about it here but forgot what it was. Thanks for the explanation!

 

I have a 2019 cr-v AMD Touring that also has “the noise”. I left it at the dealers so they could check it and they gave me a loaner which was also a 2019 cr-v AMD Touring. Parked it in my garage and a few hours later, i returned to the garage and “the noise”was happening with the loaner.😳 I thought it‘s either normal or that a recall would be coming soon. Glad to know it was normal!😁

 

That means the fuel pump must be starting up to pressurize the tank at curtain intervals.
I wonder what kind of warning you would get if something was wrong ? It sure didn't help those who had a recall on 17-062 fuel feed pipe

 

I have no idea how you came to that conclusion. That part number I posted most certainly is not the low-pressure fuel pump. The fuel pump cannot pressurize the tank with air to check for leaks; how could it? It's job is to pressurize the fuel lines... where would it even get air to pressurize with?

As far as an error message goes? You'd get an evap-emissions related code, of course, probably "Small/Large Leak Detected" would be the most likely.

 

They use the vapor pressure from the fuel. To determine the size of a small leak they modulate the solenoid and monitor the pressure drop, this provides a reference leak size. They can then monitor the tank pressure and determine if a leak is large enough to trip a code. This is called a "key off" leak test. This can only be done if the conditions are right, car has to be sitting for several hours and the temperature has to be high enough to create a mearsurable vapor pressure.

 

How do our explane the buzzing sound. ??? What could cause that ?

 

That's the sound of The electromechanical parts in the leak detection unit doing their thing.

 

That's the solenoid being modulate (pulse width modulation) on and off.

 

I rec'd an answer from Honda today for 2017 CR-V. There is a ServiceNews Article for Jan 2017 which says " Noise from Under Vehicle: This noise is caused by the vacuum pump inside the fuel evaporation leakage check module (ELCM). Depending on conditions, the pump will come on for about 15 min about 5 to 10 hours after engine shutoff. These are normal noises and don't indicate a vehicle problem."
Which is what hans471 stated. Now we have an explanation from Honda. So far mine has come on for about 1 min. 5 hrs after shut off.

 

Answer to question under vehicle noise question



I just came from the dealer who checked it out and handed me a copy of the 'ServiceNews Article'. It outlines two sounds that are normal. The first is the one we're discussing here.

--------

After Shutting off the vehicle you may hear certain noises coming from the vehicle. Here's the lowdown:

- Noise Under Vehicle: This noise is caused by the vacuum pump inside the fuel evaporation leakage check module (ELCM). Depending on conditions, the pump will come on for about 15 minutes about 5 to 10 hours after engine Shutoff.

- Clicking from Under Hood: This noise is caused by the electric brake booster (EBB) system. The system will come on for about 3 minutes every time the door is opened.

Keep in mind both of these noises are just normal vehicle operation and don't indication a vehicle problem.

--------------

Hope that helps others not go through the same fretting some of us here have......

 

the pump will come on for about 15 minutes about 5 to 10 hours after engine Shutoff.

What???

Does it say it will come on just once in that 5 to 10 hour period, or does it come on multiple times for 15 minutes each time?

 

The vacuum test is common on many cars. Its part of OBD II requirements where the car has to detect if there is a fuel vapor leak in the system. To do this they have to wait until the engine is off and the car has sat long enough that it is normalized at ambient temperatures. (This prevents false fails from changing vapor pressures in the tank). Once the car has sat the appropriate amount of time the ECM will shut the canister purge valve and the the intake vent valve, sealing off the tank. Then it will turn on a vacuum pump that will put a "vacuum" on the fuel tank. It will then shut down and the pressure sensor in the tank will look for a drop in the amount of vacuum. You do NOT want to put pressure on it! If there were a leak you would be shooting fuel out of the tank...stop and think about that.

Several conditions have to be met before this test will run. The tank can't be too full or too empty. The ambient temperature needs to be in the correct range. If you do it when its too hot the fuel will vaporized and change the pressure in the tank. So, the time window when this test runs can change based on environmental conditions. The test does not run every time you turn the car off, only when certain criteria is met. You can learn more about this code by looking up "OBD-II Small Leak Detection"

 

I have heard the noise (buzzing/humming) on my 2017 touring twice. Both times it sounds like it's closer to the rear of the vehicle. The car had been off for more than 3-4 hours each time. Both times i pushed the auto rear tailgate to open. Then i close it. The noise stopped right after both times. Are we sure this isn't a motor issue in the auto tailgates?

 

It depends on what you mean by "this". There IS an evap test pump. It DOES run several hours after engine shutdown. Is that the noise YOU are hearing? Nobody can say. But it's certainly the noise most people are hearing.

 

I've been hearing this same noise from our 2017 off and on for weeks.
Glad I came here for some piece of mind.
Mine for sure is the evap. vacuum pump thing.

Thanks again.

 

Have a 2017 EX and have noticed this sound, like a very small compressor running, several hours after running up here in northern NH in the winter, parked in the unheated-but-warmer-than-outside garage. Glad to learn that it's a normal test running; I thought it might be part of the fuel vapor collection system and it is, well-explained by the 1-10-2018 post by hans471+ . Thanks.

 

Buzzing noise

Just another one here to add my two cents to it. We've heard the noise a couple of times on our 2018 EX-L. We originally thought it had to do with the tailgate, but today it didn't stop when I opened it. So I came here and found the explanation. Thanks to all who did the research!

 

Have a 2013 Lexus RX 350........does the same thing. It's normal. Also have a 2018 Honda CRV that I heard for the first time today do the same thing. The sound is similar to that of the Lexus.