Buzzing brake master and dead battery!

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Imola Red

Imola Red

10 Year 15 Year 20 Year
Joined
Mar 10, 2006
Threads
26
Messages
212
Location
Bainbridge Island, WA
Woke up the other day in our campground to a dead battery in our 2011 LX 570! No warning, no low battery issues before. Popped the hood and heard a buzzing vibrating sound coming from the brake master vacuum canister? I think that’s what it is? But we were leaving camp for home so I had somebody help me jump it and all was good the rest of the day.

Sat overnight, went to start it and no power whatsoever. Pop the hood, alls quiet, hooked up my charger and a few seconds later the buzzing starts up again! Charger stopped and gave me a code saying “too much draw on battery while charging”. Seems to be running nonstop and killing the battery.

Yikes. Anybody have any ideas on this one? I have a video that hopefully will help.

 
It sure sounds like the accumulator. We had the accumulator go on our 08 4R but ours was a leak causing it to run nearly constant. Was a $4k repair at the dealer, probably 5-6 years ago, likely more now + the LC/LX tax. Pretty sure its the entire master cylinder that gets replaced. After replacement they hook up to techstream and run through all the bleeding routines for ABS, ATrac, etc.
 
When odd electrical things crop up, first thing to check is the battery.

How old is it?

Regardless, I would change the battery first to eliminate that as a root issue. The fact that it's been drawn down dead will have internally damaged the battery anyways.
 
The noise you hear is the brake accumulator motor. Don’t worry about the noise right now, it’s normal, just replace the battery because as TeCKis300 just said, it’s ruined.

It doesn’t take long AT ALL for a 200 series left in accessory mode to drain a battery too low to start the truck. And if It drains much lower than that it’ll permanently ruin the battery.

Either the truck was left on/accessory, something like a light was left on, a parasitic draw, or you had an internal failure of the battery.
 
So, you all think if the battery is too low that the accumulator can’t get enough pressure and it will run like that? Because shouldn’t the accumulator only run for a few seconds at a time?

Accessory could have been left on while we were camping and kids accessing things and windows etc. but damn, this battery is only two years old.
 
Last edited:
Imola Red said:
So, you all think if the battery is too low that the accumulator can’t get enough pressure and it will run like that? Because shouldn’t the accumulator only run for a few seconds at a time?
Click to expand...
It’s hard to know until there’s a good battery in there. I bet there is a voltage too low code stored for your ABS/VSC module. Get a new battery (you need one regardless) report back.
 
Imola Red said:
So, you all think if the battery is too low that the accumulator can’t get enough pressure and it will run like that? Because shouldn’t the accumulator only run for a few seconds at a time?
Click to expand...
Yes the accumulator should only run a short time, but only if there is a good battery supplying enough juice to build pressure. The message from the charger is a good clue the accumulator didn't get what it needed from the bad battery. I agree with the others a new battery is the first and very likely only step to a fix.
 
I had the exact thing happen to me in 2024 while camping and it turned out to just be the battery. The buzzing went away and everything went back to normal after I replaced it. I freaked out and thought it was the braking system and could see dollar signs in my future. The small town dealer totally ripped me off for a non-Toyota battery and I only took it there because I thought it was a bigger issue.

terrapin

Thread 'Brake Booster Pump Failed While Parked, 2010 LX570 (Resolved, Dead Battery)'

I am stuck at a campground near Silver City, NM. I have been here for a few days and yesterday I moved my trailer to another campsite. Everything was fine, no dash lights or any warning. Up to that point the brakes have been fine.

After I moved the trailer, I parked my vehicle and left it for a few hours. When I went to open the tailgate and there was absolutely no power. That was when I noticed a buzzing sound from under the hood. It appeared that the brake booster pump had been running non-stop for at least four hours. I disconnected the battery and let it sit overnight.

This morning I...
 
Yes, too little voltage and electronics start doing unpredictable things. First step with any funny electronics business should always be the battery.

Easy to draw down a battery when camping. Especially one that is already weak. Door, interior lights, and other things on for longer durations.

Without due diligence in turning lights off camping, upgrading interior bulbs to LEDs can help minimize draw on the battery for camping trips. Makes a substantial difference.
 
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