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Evaporation Leak Check Module - buzzing sound when car is off and idle?

46K views 30 replies 15 participants last post by  Mikestony 
#1 · (Edited)
Does anyone notice a somewhat steady buzzing sound from the car when it is parked and off in your garage or parking space when it’s really quiet outside? It’s kind of like the noise fluorescent light bulbs make when turned on.

I checked some Prius forums and it appears to be normal for that car.
They said it's the fuel evaporation leakage check or something.

I’ll have to check the manual to be sure else I need to go see my dealer.
 
#10 ·
Buzzing while parked

Nothing unusual with my Touring ( love it - none of the problems listed above) but last couple of days , after parking my car in my garage - a weird buzzing , electrical humming was coming out of the back of my car . When I opened my trunk the buzzing was louder. I started the car and after that the buzzing disappeared. I’m thinking it’s either the sound system or , worst, the battery ... Anyone else experiencing the same issue?
 
#11 ·
Nothing unusual with my Touring ( love it - none of the problems listed above) but last couple of days , after parking my car in my garage - a weird buzzing , electrical humming was coming out of the back of my car . When I opened my trunk the buzzing was louder. I started the car and after that the buzzing disappeared. I’m thinking it’s either the sound system or , worst, the battery ... Anyone else experiencing the same issue?
Yes. It’s normal. It should be the vacuum pump inside the fuel evaporation leakage check module.
 

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#15 ·
Humming sound coming from trunk. Car is off

Hi, I'm the guy whose brand new 2019 Insight was towed to the dealer the first day after I bought it. The car has been running great for the last 6 months and 6K+ miles.

Today, however, I noticed a humming sound coming from the driver's side trunk area while the car was turned off in my garage. The car had been parked there for several hours. It sounded like a small motor whirring away. I backed the car out of the garage, shut the car off and the sound stopped. Weird.

Does anyone know if there might be a motor of some sort located there causing this sound?

Thanks in advance.
 
#16 ·
Hi, I'm the guy whose brand new 2019 Insight was towed to the dealer the first day after I bought it. The car has been running great for the last 6 months and 6K+ miles.

Today, however, I noticed a humming sound coming from the driver's side trunk area while the car was turned off in my garage. The car had been parked there for several hours. It sounded like a small motor whirring away. I backed the car out of the garage, shut the car off and the sound stopped. Weird.

Does anyone know if there might be a motor of some sort located there causing this sound?

Thanks in advance.
Glad to hear your car has been running well after initial incident. I think the noise you're hearing is the Evaporation Leak Check Module. There's a (very) small blurb on it on pg 14 of the Owners Manual, and additional context earlier in this thread:

"After shutting off the engine, you may hear certain noises coming from the vehicle. 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 minutes about 5 to 10 hours after engine shutoff. This noise is just normal vehicle operation and don’t indicate a vehicle problem."

 
#21 ·
And a description of what happens during the ruckus of the Evaporation Leakage Checking Module's tests:
  • The evaporative emission control (EVAP) system in your Honda prevents fuel vapors from escaping into the atmosphere. The fuel vapors from the fuel tank are absorbed and stored by charcoal pellets in the charcoal canister.
  • The vent control valve is controlled by the engine control module (ECM) and allows air to flow into the charcoal canister to purge the gas vapors into the engine air intake to be burned.
  • The flow of the gas vapors from the charcoal canister to the engine air intake is controlled by a purge valve.
  • Both the vent control valve and the purge valve are usually open when the engine is at normal operating temperature; however, the ECM occasionally performs leak tests to ensure the evaporative emission control system is working properly.
  • During the leak test, the ECM closes the vent control valve and purge valve to create a vacuum.
  • If the EVAP system does not maintain the pressure, the ECM flags an evaporative emission control leak.
 
#22 ·
We could have just found our vibration issue...

If I remember correctly, fuel trims are fixed during close loop, and if the evaporations test happens during close loop, it could technically affect idle. When my truck had a clogged charcoal canister, during closed loop, it would have a "misfire" like idle, rougher than normal. Not saying that my truck is a direct comparison, but changing vacuum, or even the slight amount of fuel that gets burnt through the Evap. system, could be a suspect in our "vibration at idle" issue.

These tests under normal conditions (driving) would most likely be imperceptible to anyone (unless looking at engine data), but at idle, the engine can't transfer the vibrations through the tires, and instead is forced to transfer it through motor mounts.
 
#25 ·
I think I finally heard the evap test sound for the first time tonight. I've had my Insight since 8/2018. It was exactly the same sound as the aforementioned Clarity video demonstrates. The car had been parked in the garage for 5.5 hours. I had just arrived back home in another car from my daughter's dance class. It wasn't difficult to miss in a quiet garage after the garage door closed. Even though I knew what it was, I was surprised since I had never heard it before. It's nice to know my Insight is taking care of itself.
 
#26 ·
I experienced that sound(sounds like a loud hair trimmer :p) for the first time a few months ago. I heard it from my 2nd floor apartment and thought someone was running some sort of machine in the middle of the night. Looked out of the window and saw nothing except for the sound coming from my Insight.
 
#27 ·
Tonight I went to grab something out of the car and as I was about to leave I heard a humming sound. Traced it back to coming from underneath the car near the left rear wheel.
I'm assuming it's something to do with the HV battery, as when I remote started the car (unfortunately I didn't record that), it made a bunch of clicking (relay type) noises and then stopped before the engine kicked on.
But the sound was behind the rear axle, and more in the trunk. It wasn't very audible inside the car (ie, not coming from underneath the rear seats where the HV battery is as far as I understand). I've posted a video below. On another recording, I move my phone from the rear bumper to the axle, and the sound is loudest 3/4 of the way towards the rear wheel axle.

Anyone know what this is? Is this normal? (Could be, I don't generally sit out there and listen to the car)

 
#28 ·
Tonight I went to grab something out of the car and as I was about to leave I heard a humming sound. Traced it back to coming from underneath the car near the left rear wheel.
I'm assuming it's something to do with the HV battery, as when I remote started the car (unfortunately I didn't record that), it made a bunch of clicking (relay type) noises and then stopped before the engine kicked on.
The video humming and location sounds like the vacuum pump inside the fuel evaporation leak check module, similar to the Clarity video example in post #20. It's not related to the HV battery, but moreso the fuel area (which is located behind th HV battery). The pump is known to run for 15 minutes after the engine has been shut down for 5-10 hours.

Separate from the evaporation leak check module, I think the clicking noises during remote start might be the electrical relay checks/interlocks (?). Have you used remote start before, or is the first time you've used and observed?
 
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