Strange Sound in a brand new Subaru

We have an entry model 2010 Subaru Outback with the CVT transmission. It?s still under the manufacturer?s warrantee. We noticed soon after buying it, that every time we turn it on and start driving it, there is a strange clunking sound that comes from the rear of the vehicle. It sounds like we are running over a small tree branch and crushing it, but there is no branch, stick, twig, anything. We have even taken it to empty parking lots to ensure that it?s not something near our house. Every time, after starting it and driving, we get the sound. There is no movement or feeling, just the sound only.

We took it to the dealer, the mechanic drove around with us, and said he heard the sound and was concerned. He said there was a recall on some of the earlier 2010 Outbacks due to some problem with the transmission case, but that our vehicle was built after the recall issue was resolved.

After having our car looked at for almost 2 full days, the service manager called us back, and told us that nothing was wrong. We asked about the sound, and he said it?s just the ABS system doing a self diagnosis and that is why we only hear it after we turn the car on and start driving. He said the vehicle has to be in motion to do the diagnosis, and so it waits until we start driving. He said most people can?t hear it.

Is this answer a load of BS? Or could this be the truth?

Take it to a different dealer and see what they say. You have a warranty; use it. Good luck.

A lot of folks have been needlessly troubled by the sound of the ABS self-test on a new car.
The noise from an ABS self-test varies considerably from one make to another, and can even vary to some extent from one car to another within the same model range.

Some folks claim to have never heard this noise, so it is even possible that some makes and models do not make the self-test apparent. All I can tell you is that it has been obvious on my last 5 cars, and those were a Honda, a Ford, and three Subarus.

The scenario for the ABS self-test is as follows:
It takes place when the car is started after sitting for several hours.
It takes place after putting the car into gear and driving anywhere from 10 ft to 25 feet.
It makes the noise only very briefly, and not continuously.

The noise itself can sound like a clunk, a buzz, a vibration, or a mild “bang”, and can sometimes be felt in the brake pedal.

I believe that what you are hearing is the normal sound of the ABS self-test, but I suggest that you retain the documentation of your visit to the dealership and the complaint. In the unlikely event that it turns out to be something else, you are covered at least through the warranty period, and if it is documented that you complained about a particular issue during the warranty period, it is sometimes possible for it to be covered even after the warranties expire.

What you were told is very likely to be the truth.
Have you bothered to read what your Owner’s Manual has to say on this topic?
I can virtually guarantee you that this topic is covered in the manual.

Yes, its the ABS system doing its self check on the first drive after being off for several hours.

It usually happens around 9 mph.
Next time you go out to your car, barely accelerate your car, and see if the sound happens at ~9 mph. After it makes the noise, pull out your owners manual, and read the section on your brakes, and see what it says.

In fact, just to help you out, here’s what is says:

ABS system self-check
You may feel a slight shock in the brake pedal and hear the operating sound of ABS from the engine compartment just after the vehicle is started. This is caused by an automatic functional test of the ABS system being carried out and does not indicate any abnormal condition.


…and, even though the ABS self-test noise emanates from under the hood, the nature of unitized body construction is that noises are frequently “telegraphed” to other parts of the car. Even though you think that the noise is coming from the rear of the car, it may actually be coming from underneath the hood.

Insist that you want to sit in another “like model” and hear the same noise, easy enough.

Well, with my Nissan Altima, the ABS test noise sounds like it is coming from the right front wheel, but I know for a fact that all the ABS components are just in front of the drivers seat, inside the engine bay.

Sounds does funny things when it travels through both solids and air.


I’m in agreement that you should test another car to see if this same noise exists.
Why would there be an ABS noise from the rear?

Regarding Recalls, sometimes vehicles that are not listed as part of a Recall may suffer the exact same problem as the Recalled ones.
Example. Some models of Hondas are under a Recall for failed ignition switches but many of the Hondas not covered also suffer switch failures. Automotive/governmental politics at work.

Hi emaon256
Regarding the strange noise from your 2010 Subaru, I think your garage are right. I have a 2006 Honda CRV & it took me awhile to find out the clunk sound like my doors were all locking, I have the big shop manual for my CRV & it explained that sound was the ABS doing its check. On mine it happens when I reach about 12 MPH. I don’t see anything about it in the manual in the glove compartment though.

I tried searching my manual(PDF document) about an ABS self test, but the search function doesn’t show anything regarding it. Even a few variations on “abs self test” did not yield any results.
I know my car has ABS because it’s a 2010 and I felt the pedal shuddering when I tried pushing the pedal harder than I should have on my street one morning testing the car out with what little snow there was on the street.

My 2010 Outback with CVT makes the same sound. Not to worry. The 2010 / 2011 Outback with a CVT has a variable clutch that applies more power to the rear wheels under slippery conditions. This system also self tests when you first turn on and start to drive the car. You are most likely hearing this - it kinda sounds like light banging and also occurs when the car first starts to move.

The 2010 Outback manual uses a viscus coupling and the H6 system uses something they call a VDT system - which is a planetary gear configuration with clutch. Each has their pluses / minuses.

And we got an answer. We went back to the same dealer and asked to drive another identical Subaru as was suggested, and the sound, which specifically came from the rear differential, did not occur. They still insisted it was the ABS system and would not do anything.

We have had other cars with ABS systems, and they all made a low buzzing sound, and we felt it in the break petal, much as the manual describes. This sound did not act like the manual’s description.

We finally made the long trek to another dealer. The mechanic rode in the vehicle with us, heard the problem, and said that is in no way related to the anti-lock breaks, and that the other dealer was feeding us a load of bull. He lifted the vehicle, and determined was a solenoid in the rear transfer case that was not bolted down all the way, so as it engaged, it also moved itself, making the noise. It has now been fixed.

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Hello sir quick question any picture were the solenoid transfer case? Im goin to a dealer this week. In having trouble same as your sir thank you sirb

C’mon . . . :rolling_eyes:

let dead and buried stay that way, please :skull:

I think @tomhonda24 was asking specifically about the issue addressed above – so it’s not dead and buried to him.

However, in view of the fact that Subarus do NOT have transfer cases, his question is…very curious…and is unlikely to lead to a satisfactory answer!

Fair enough. And I’m a casual reader, for sure, who knows nothing about transfer cases. But I commented because the response to the question, however misdirected by tomhonda, did not even acknowledge the fact that the question wasn’t related to the thread he was posted in. I think one could make the argument to create a new thread, but instead the guy got a skull and a sigh. :slight_smile:

Ops sorry if i ask it and didnt think this thread is dead hehe my bad… just asking @emanon256 cause the solved the problem of his car :slight_smile: i got the same issue sorry guys…

Unfortunately I don't have a picture, as it was under and I believe inside the car. But it is still working great since the repair and we have had no further issues or noise.

I have a new 2018 Subaru Outback which emits a slight, for lack of a better term, “groan” momentarily as described above. I have spoke to the local dealer a number of times getting the story they have never heard of this before. On one occasion it was stated it is the ABS testing. I just purchased a used 2015 Outback with 57k miles. Guess what. The same thing. I am leaning toward the ABS response. Why don’t they just tell people!