Buzzing behind driver side dash?

[S1w]

When I start my '03 v6 4x4 Limited 4Runner I get a buzzing for about 8 seconds which I can feel and hear. Then it happens about every 3-4 minutes for 3-4 seconds.

I believe it has something to do with the ABS system as an actuator or something. I was told it should only happen at start up but it happens continually.

Can anyone confirm what I'm hearing, if it is normal and if not what the issue is?

I can't believe these were sold new with a buzzing that often that everyone in the car can hear.

Thanks for the help.

 

[ToyoTech]

sounds like your abs system. it should only do it at start up. if it does it often, this could mean your accumulator isnt holding pressure and causing the pump to come on but this also means you would get an ABS light. a bad sensor could do this as well

 

[BlackWorksInc]

The HydraBoost unit will kick in when you start the vehicle and roughly every other time the brake pedal is depressed. This is normal for the vehicle, it should be about the sound of a vibrating phone slightly muffled with the windows up and radio off. If the unit is constantly cycling WITHOUT depressing the brake pedal, you may have a hydraulic leak within the unit depressurizing the nitrogen charged acumulator tank.

I cannot seem to find the section in the repair manual describing the proper operating characteristics of the Hydraboost unit that I used to diagnosis my unit earlier this year. I'll see if I can find it and post it up here.

 

[JB.]

The HydraBoost unit will kick in when you start the vehicle and roughly every other time the brake pedal is depressed. This is normal for the vehicle, it should be about the sound of a vibrating phone slightly muffled with the windows up and radio off. If the unit is constantly cycling WITHOUT depressing the brake pedal, you may have a hydraulic leak within the unit depressurizing the nitrogen charged acumulator tank.

Mine runs about 4 times every minute in park, no brake. Has been doing it for a few months. Brake fluid level hasn't budged. Possibly a coincidence, but I started noticing the noise after replacing the battery after having it disconnected all night (there was also a jump start before that). Can you think of any connection between the two?

If not, would you expect the situation to deteriorate quickly, or might the HydraBoost be doing the same thing a year from now.

 

[BlackWorksInc]

I don't know.... I don't remember mine kicking in so often when in park... I'll double check tomorrow and see if I can replicate your situation.

 

[zonianbrat]

I just replaced my entire hydroboost unit to the tune of a 1000 bucks and it was a used unit. I noticed the buzzing sound was happening like once or twice a minute. It progressively got worse week by week. The days before I had it repaird the pump was kicking on about every 7-8 seconds. There was also a very noticable vibration in the brake pedal. The new unit is really quiet and the pump only comes on like every 3 brake depressions. Sorry to give bad news but if you decide to repair it before it gets worse get ready to spend some money. Here is my thread explaining my issues and frustrations.

http://www.toyota-4runner.org/4th-gen-t4rs/129652-might-have-trade-off-ridiculous.html

 

[S1w]

Like you said....

I took the 4Runner into the dealer today for an oil change so I could have them look at the buzzing sound. They said it was the master cylinder and it needed to be replaced to the tune or $2700. Well, I plan to keep it like it is until it gets worse or I find a used part well under $1000.

Any recommendations on where to find used parts at a good price? What years fit my 2003 v6 4x4 Limited?

 

[BlackWorksInc]

I took the 4Runner into the dealer today for an oil change so I could have them look at the buzzing sound. They said it was the master cylinder and it needed to be replaced to the tune or $2700. Well, I plan to keep it like it is until it gets worse or I find a used part well under $1000.

Any recommendations on where to find used parts at a good price? What years fit my 2003 v6 4x4 Limited?

I believe '03-07 should fit your vehicle, You can get one from http://www.villagetoyotaparts.com/showAssembly.aspx?ukey_product=2086204&ukey_assembly=322697&ukey_make=1021&ukey_model=14403&ukey_driveline=6157&ukey_trimlevel=14102&modelYear=2003 for about $1700. Labor should be an hour or two to physically replace the unit and then have someone with a Toyota or ABS capable scantool bleed the brakes and system.

 

[kerryjosber]

good idea,I'll double check tomorrow and see if I can replicate your situation.thanks

 

[zonianbrat]

I took the 4Runner into the dealer today for an oil change so I could have them look at the buzzing sound. They said it was the master cylinder and it needed to be replaced to the tune or $2700. Well, I plan to keep it like it is until it gets worse or I find a used part well under $1000.

Any recommendations on where to find used parts at a good price? What years fit my 2003 v6 4x4 Limited?

I will try to find the number of the yard where I bought my used hydroboost unit. It's too bad nobody can rebuild these because I have my old hydroboost unit just sitting in my garage.:shrug:

 

[e10pvmt]

im converting to hydroboost on my 03 2wd and wont need the assembly...lookin for 500 shipped...works perfectly...112k miles

 

[BSG_75]

The HydraBoost unit will kick in when you start the vehicle and roughly every other time the brake pedal is depressed. This is normal for the vehicle, it should be about the sound of a vibrating phone slightly muffled with the windows up and radio off. If the unit is constantly cycling WITHOUT depressing the brake pedal, you may have a hydraulic leak within the unit depressurizing the nitrogen charged acumulator tank.

I cannot seem to find the section in the repair manual describing the proper operating characteristics of the Hydraboost unit that I used to diagnosis my unit earlier this year. I'll see if I can find it and post it up here.

I have an 02 4Runner and mine does this too, ends with a click on the passenger side. Does it at startup, and seems to almost every time I brake. Wonder if I have the same system in the old girl. :shrug: