Hello all,

I've noticed a strange noize in my 01 4Runner. It seems to happen randomly and on a fairly frequent basis; at least a few times each time a I drive the vehicle. From the front right of the cabin, sounds like it could be coming from the engine compartment (behind the firewall) or possibly under the dash, but generally from the front right when you are sitting in the driver's seat. I hear an electric motor type of buzz for about 5 seconds followed by a click or pop that sounds kind of like a soleniod clicking. You could say it sounds a little bit like a blinker soleniod, but it's a bit deeper and heavier.

I notice it mostly when I'm slowing down to stop at a light or stop sign, but I can't say whether it happens while driving at speed. I'm sure it's possible that it is happening at speed and the road noise is just loud enough to cover it up.

Does anybody know what this is? I've searched on the keywords I can think of and can't seem to find anything on it.

Keywords: buz, buzz, electric motor, click, pop, soleniod, right front

*I know this is a shot in the dark, but try (just try) and see if a loose piece of material is flapping around in the front right wheel well.

*Something with the vent motor?

*Perhaps a rattle. There is some fix you can search for involving the air bag assembly. I think this was a Tacoma problem though.

Good luck

Dwitchman, I've recently owned a '01 4Runner and I have observed exactly the same, word-to-word, problem in my vehicle too... its kind of irritating me alot but couldnt find what the reason is. Did you, by any chance, get to know what it is? Thanks in advance.

Hey Runner01,

No, I still don't know what it is. But I'm not convinced that it's actually a problem. Benzene had some interesting suggestions; it's definitely not something loose in the wheel well, way too mechanical sounding for that. I guess it could be something like the vent motor, but it does it whether the fan is on or not. And I don't think the air bag rattle really fits the description here.

I wonder if it has something to do w/ the particular model, e.g. SR5, Sport, Limited, 2/4 WD. What model do you have?

Mine is an SR5 2WD
Today morning I tried to find if its happening in a timely manner... but I guess not, first time it happened for 2 mins... nxt 4 mins.. so its kind of, as you mentioned, random. My nxt 'Test' would be to find if it happens only while running... cus I feel like it happens even when the vehicle is at halt but in 'D' (I am not sure what I can get to with that)
I dont want to take it to a machanic without knowing what exactly it is.
I will keep researching and will let u know if I find something.

Okay, mine's a SR5 4WD Sport, so I guess we can rule out the 4WD system :)

Have you ever reproduced it w/ the engine off, ignition on? I've only ever heard it w/ the engine on and in drive, like you said. But it seems to happen regardless of whether I'm moving or stopped at a light.

Yes, when theres considerable time between rides like first time in the morning or while leaving home from work... I can hear it (with buzz sound a bit loooonger than usual) when I turn on the ignition (engine off)... hmmm which means we can rule out the engine too (I just realized it)..
ps: the sound seems to going all the way back to the 'gas' cap

The noise you are describing is the ABS computer self-test. On some 4Runners (like mine), the vehicle performs this test after every few times you use the brakes. It also performs the test shortly after start-up.

It is annoying, but harmless. I have had the dealer check mine out and it is "normal". I have also talked to a number of people on other forums with the same issue and none have had any problems related to this.

So, you can relax and turn up the radio.

LOL, that's what I've been doing (the radio). I had a feeling it might be something like that. I had an Audi that used to do something similar, although it sounded a bit different, but it only did it right after starting it.

Do you know where the ABS unit that makes this noise is located? I'd like to catch it in action to insure that we're talking about the same thing. Although it definitely sounds the same.

Thanks.

Not sure where it is located, but the noise definitely comes from the right front. I don't know if you'd be able to see anything anyway. I've heard the noise described in several ways. Mine is a hisssssssss-pop. The hiss lasts for 3-5 seconds.

One of the very few things that bothers me about my 01 4Runner. It is really an outstanding vehicle.

Good luck.

HUH! wow what a relief... thats a real good news, thanks Phil. But as dwichman mentioned it would be a grrrreat satisfaction if we could see that in action :)

I had the exact same problem, almost word for word as described above. I am very relieved to find out that its something normal. I have to say it's a bit annoying, but I can deal with it knowing all's okay. I'm getting ready to ship my 4R to Amman Jordan where I know I will be needing a dependable vehicle and this is good news. Thanks!