ABS, VSC Trac VSC OFF , and Brake Lights Lit, Constant Beep or Alarm Sound, No Brake Pressure
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I changed the whole brake assy as advice by my mechanic. When I checked the faulty one, I discovered it was the motor that was faulty which I also repaired and keep as spare. It was only the brush inside the motor that was changed.ABS VSC Trac and VSC OFF Light have been illuminated intermittently for a few weeks. I just assumed it was a precursor to another P0420 error code (Check engine, VSC TRAC and VSC OFF Lights) or a fouled up wheel sensor which fixed it self after a brake job several years ago, or something benign. Today i was just driving casually along city streets and nothing was hot or over-worked, at least this particular day, and the ABS/VSC lights were lit like they have been recently, and then i get a beeping sound and the BRAKE (normally indicating Parking Brake is engaged) lights up and a beeping started from the dash. Brakes were working fine at the time. So we got to our next destination and i tried turning the truck off and back on and it still beeped like crazy. I went into a store for 20 mins and came out and it was still beeping but now i had no brake pressure unless i stood on the pedal. Several short and slow driving cycles later still have only soft brake response and beeping will not cease. I check the ECU for codes with a bluetooth code reader and there are no codes. I have to get my cable back before i can connect to Techstream and see what that says. Is there any basic troubleshooting i can do to see whats going on?
The motor can be manually checked by applying 12vdc to positive and negative contacts and see if it does work.
OK, my ABS light and alarm started yesterday. I still have brake pressure. Is it safe to drive to a mechanic a few miles away or is it possible to lose all pressure?
EDIT: I just did as recommended and tapped on the booster pump with a screwdriver and sure enough it came to life. Safe to assume this is a temporary fix and I will need to take it to a shop for replacement?
EDIT: I just did as recommended and tapped on the booster pump with a screwdriver and sure enough it came to life. Safe to assume this is a temporary fix and I will need to take it to a shop for replacement?
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2001LC
SILVER Star
Not safe to drive. If brakes pedal was pumped say ~3 or 4 times, and motor did not come on until tapped on motor.
If motor fails to start, while driving, you'll get alarms and maybe 3 pumps on pedal, before no brakes.
If motor fails to start, while driving, you'll get alarms and maybe 3 pumps on pedal, before no brakes.
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OK, my ABS light and alarm started yesterday. I still have brake pressure. Is it safe to drive to a mechanic a few miles away or is it possible to lose all pressure?
Yes - if you totally lose the motor/system, your brake pedal will go to the floor when you first press it. What you do then: pump it twice, and it will come back halfway up, but you'll 2x the pedal pressure to stop the truck. If you leave a large cushion between you and the cars in front of you, you can safely drive it to a shop or home. This is what happened on my '99 - there may be other failure modes where you truly lose all brakes. If you crash and burn, I take no liability with this posting!
Yes - if you totally lose the motor/system, your brake pedal will go to the floor when you first press it. What you do then: pump it twice, and it will come back halfway up, but you'll 2x the pedal pressure to stop the truck. If you leave a large cushion between you and the cars in front of you, you can safely drive it to a shop or home. This is what happened on my '99 - there may be other failure modes where you truly lose all brakes. If you crash and burn, I take no liability with this posting!
Thank you both, sounds like I should schedule a tow truck.
2001LC
SILVER Star
I've seen some have no bake others have some, with 2 or 3 pumps. Not safe to drive.
Thank you for the responses folks. I never did fully lose all brake pressure but I had it towed to a shop. Sure enough full failure. For those in ATL, couldn't recommend LexTechs enough. Very professional and awesome work.
Hi everyone, sorry to necro this thread but so much good info in here.
On my 2002 with 204k miles, I'm having intermittent constant alarm issues with all the various warning VSC/ABS warning lights.
It only just started in the last 36 issues, but the issue comes and goes so far. I've stopped driving the truck as I understand the danger.
Initially, I'm unable to find any definitive reason for the alarms. No obvious leaks I can detect, except there is a little wetness around the plastic reservoir and then what looks like an old leak down below. And the reservoir looks like it may have been replaced already at some point because its not super yellowed like an old PS resi.
Based on my photos, can anyone tell if any of the MC related parts have been replaced?
If not, is the correct play to grab the list of parts from post #43 and then the pump assembly 47960-60010 (or have it rebuilt at one of those shops?)
Thanks all!
On my 2002 with 204k miles, I'm having intermittent constant alarm issues with all the various warning VSC/ABS warning lights.
It only just started in the last 36 issues, but the issue comes and goes so far. I've stopped driving the truck as I understand the danger.
Initially, I'm unable to find any definitive reason for the alarms. No obvious leaks I can detect, except there is a little wetness around the plastic reservoir and then what looks like an old leak down below. And the reservoir looks like it may have been replaced already at some point because its not super yellowed like an old PS resi.
Based on my photos, can anyone tell if any of the MC related parts have been replaced?
If not, is the correct play to grab the list of parts from post #43 and then the pump assembly 47960-60010 (or have it rebuilt at one of those shops?)
Thanks all!
2001LC
SILVER Star
Looks like original brake master. The cap is on backwards. But they usually don't leak even if on backwards. Provided down tight.
I see something a bit strange. That is you center forward compartment is draining slow. I see this in reservoir that have clogged screens. But those reservoirs are stained. Your's looks clean.
Has this reservoir been off and cleaned?
If I didn't see wets on top of reservoir, around cap. I say your leak, is between ABS (black box with aluminum block) & master. But with cap area wet, it may be from there.
Are you getting the sound: screaming banshee AKA dying segal, with bubbles coming up front of reservoir as you hear sound.
You may want to read up a bit:
Brakes ...... Overdue write-up.
First and foremost: Brakes should only be worked by those, with high level of mechanical abilities and experienced with brake systems. With the age of all 100 series today, in our aging fleet. Any issue, with brake master assembly. IMHO, best and safest course of action. Have the whole brake...
forum.ih8mud.com
Looks like original brake master. The cap is on backwards. But they usually don't leak even if on backwards. Provided down tight.
I see something a bit strange. That is you center forward compartment is draining slow. I see this in reservoir that have clogged screens. But those reservoirs are stained. Your's looks clean.
Has this reservoir been off and cleaned?
If I didn't see wets on top of reservoir, around cap. I say your leak, is between ABS (black box with aluminum block) & master. But with cap area wet, it may be from there.
Are you getting the sound: screaming banshee AKA dying segal, with bubbles coming up front of reservoir as you hear sound.
You may want to read up a bit:
Brakes ...... Overdue write-up.
First and foremost: Brakes should only be worked by those, with high level of mechanical abilities and experienced with brake systems. With the age of all 100 series today, in our aging fleet. Any issue, with brake master assembly. IMHO, best and safest course of action. Have the whole brake...
Never heard that sound come out of either of my two LCs.
So you think it’s possible it’s the rubber grommets that connect the reservoir into the metal assembly?
I do think it’s possible one of my brake soft lines right before the caliper has a tiny weep hole in it. 3 were dry and one was a little bit wet towards the caliper, front right.
So I’m wondering if maybe I’m losing pressure in that line. I can’t get it to leak or lose fluid after pumping the brakes 40+ times so not sure
2001LC
SILVER Star
I never see those reservoir grommets leak, unless reservoir has been removed.
FR brake line is often wet, from PS fluid from above. Degrease and clean, then have helper press brakes pedal hard and hold, with IG key on. Look for leak & bubbles in lines, while brake pedal held down.
"On my 2002 with 204k miles, I'm having intermittent constant alarm issues with all the various warning VSC/ABS warning lights.
It only just started in the last 36 issues, but the issue comes and goes so far"
? 36 issues? HUH!
If while driving, you may be actatiing you VCS, which is through the ABS system. This happens very often do to loose wheel bearings. I've also seen loose steering, ball joints, bad R&P mount, bad stabilizer system activate ABS/VSC.
? Condition while driving? Like ruts in road, in sweeping turns, etc.
Did you read through link on brakes I provided?
What concern me about your master, if fluid on outside of it, for one.
But also as noted above. This chamber drain slow. To slow is indication of clogged screens.
That's exactly the one that was wet. Will try that later today.
Based on your note in the thread you linked about the front lines, I think that might be my issue.
Typo. Meant to say last 36 hours.
I've done a ton of work including all brand new OEM bearings, races, steering rack, inner/outer tie rods, shocks, etc.
I do occasionally have a pop in the front left that sounds like possibly a ball join going out, and I do have a vibration that I think might be from a bent wheel. Brand new tires just a few months ago and the vibration has remained since I got the truck.
Perhaps its related to this vibration that the system activates, but it will occasionally beep on startup too, so that doesn't seem to correlate.
Seems more likely that it's one of the rubber brake lines that's got a small leak in it.
Yes, I read it last night and again just now to make sure I understand.
My booster turns off relatively quickly, like 25 seconds or so at most. I'll count it today.
EDIT: I counted and after the car sat overnight, the pump ran for 35 seconds without touching the pedal.
Ok, then maybe I'll swap the rubber lines and replace the resi just in case its leaking. Not expensive to do those things first to start, since I think the pump is still good.
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2001LC
SILVER Star
This is rarely a brake line leak. 99 out of 100, it is the PS reservoir and it's cap, and or hoses. The leak drips onto brake line.
First I'd check for codes, current & pending. See if code points to something. Keep in mind, ABS/VSC shutdown, when most any system has a fault.
Then I'd check wheel bearings for play. If hub wobbles, wheel speed sensors get a false reading on speed. I'd also check the speed sensor for cracks, which prying them out will cause. Also, that the 10mm bolt is torque to ~70INCH-lbf. (5ft-lbf). Also that the wire is route properly and clips into to harness on fender well, sungly.
I'd put brake reservoir cap on correctly. Note, cap has a pointer & reservoir has open and close written on it. Point cap pointer to open, press down on cap and turn 1/8 turn CW to close. Then use a hose and wash off all brake fluid, top to bottom. Make sure it's dry of and brake fluid. Then watch for wetness/leak point of origin.
The "occasionally beep on start up". The beep may be brake alarm. It could be low brake pressure alarm. But, until we press on brake pedal, pressure is not released into brake lines. So if "alarm/beep" before pressing pedal, if this is brake related and you hear alarm. It could be booster motor. I've seen these motors work intermittently. Which I talk about in my brake thread. It could also be a leak in brake master assy, resulting in pressure loss.
Also, you done a lot of work. The why you replace so much, and did this issue start after, may yield clues.
Also (as I ask before) driving condition when ABS/VSC activates, is important to know. This too, yields clues.
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Based on your excellent help and my troubleshooting this afternoon, it seems like its the booster motor.
When I turned the key to on, no pressing brake, and engine off the alarm started within about 5 seconds.
I recorded a video of what I'm hearing now:
If I pump the brake pedal 40 times like you described, then turn the key to on, the motor does as show in the video. Sometime it runs a little longer, but then the alarm will sound pretty quickly now all the time. Seems like the motor is getting worse and worse.
I still do have brakes, although I'm only tried going back and forth in my driveway.
This seems to me like booster motor. Do you agree?
To answer your question about why I've replaced so much. The PO heavily neglected this truck and I bought it at 199k miles, so I've replaced tons of parts with OEM to try to make this truck as reliable as possible. I haven't replaced anything or touched the truck in 3,000 miles by this point so I don't think it's anything to do with the previous repairs.
Thanks again for your help
2001LC
SILVER Star
All the video is shows, is booster motor did run. Looking at level of reservoir. I would not expect it to run very long. Unless your fluid low, accumulator is already charged. Test inconclusive!
When we pump brake pedal 40 times, w/IG key off. This evacuates accumulator (the gold cylinder you touch and wiggled) fluid, back into reservoir, bleeding off all fluid and pressure from accumulator. The accumulator will also bleed off pressure/fluid, just sitting IG key off, over time.
Try this: Read what is embossed on reservoir.
Pump pedal 40 time key off. Note the level in reservoir come up. Tune IG key on, booster motor will now run. Note how level in reservoir drops, as in charges/pressurized accumulator.
Does any read this. Not many!
I'm going to point to your issue, of reservoir center front chamber, slow to drain. Look at picture a few post above, with red arrow point to your reservoir front center chamber. It's level, is higher than other chambers. Now compare to this picture below. Which was take after IG key turned on to charge accumulator, which took 36.2 seconds. Battery voltage was at ~12.5V. Battery must have full charge for the booster motor run time test.
The level in all chambers drew down at same rate. This is a good reservoir with clean screens.
Here' one that was puking fluid out the cap. Fluid is on reservoir and was on master. This master had to be replaced. It was not safe to drive.
The black (gunk clogging) in screen was mostly washed out, just before picture taken. I left some gunk just for the picture. It was coating all the screens.
I've seen the issue of center chamber slow to drain before. This is due to, clogged screens. If screen in reservoir clogged. There is at least one filter in ABS unit. Your master is heading for trouble. May be tomorrow, may be years from now. Who konows!
*** The clogged screen resulted in, fluid backing up and blowing out the cap. Which you may have going on.***
I'm not saying this is your alarms or ABS/VSC. I'm saying if not now your issue, it will be. I'd be saving for a master, if not looking for a deal today.
When we pump brake pedal 40 times, w/IG key off. This evacuates accumulator (the gold cylinder you touch and wiggled) fluid, back into reservoir, bleeding off all fluid and pressure from accumulator. The accumulator will also bleed off pressure/fluid, just sitting IG key off, over time.
Try this: Read what is embossed on reservoir.
Pump pedal 40 time key off. Note the level in reservoir come up. Tune IG key on, booster motor will now run. Note how level in reservoir drops, as in charges/pressurized accumulator.
Does any read this. Not many!
I'm going to point to your issue, of reservoir center front chamber, slow to drain. Look at picture a few post above, with red arrow point to your reservoir front center chamber. It's level, is higher than other chambers. Now compare to this picture below. Which was take after IG key turned on to charge accumulator, which took 36.2 seconds. Battery voltage was at ~12.5V. Battery must have full charge for the booster motor run time test.
The level in all chambers drew down at same rate. This is a good reservoir with clean screens.
Here' one that was puking fluid out the cap. Fluid is on reservoir and was on master. This master had to be replaced. It was not safe to drive.
The black (gunk clogging) in screen was mostly washed out, just before picture taken. I left some gunk just for the picture. It was coating all the screens.
I've seen the issue of center chamber slow to drain before. This is due to, clogged screens. If screen in reservoir clogged. There is at least one filter in ABS unit. Your master is heading for trouble. May be tomorrow, may be years from now. Who konows!
*** The clogged screen resulted in, fluid backing up and blowing out the cap. Which you may have going on.***
I'm not saying this is your alarms or ABS/VSC. I'm saying if not now your issue, it will be. I'd be saving for a master, if not looking for a deal today.
Wow, ok great info! I'll monitor the levels again as you describe.
Do you think taking off the reservoir and dropping it in my ultrasonic cleaner to fully clean it, then reinstall might contribute positively to fixing this issue?
I have to place another order for parts for a different car soon, so if I need anything for this LC I'd like to do it sooner than later
Do you think taking off the reservoir and dropping it in my ultrasonic cleaner to fully clean it, then reinstall might contribute positively to fixing this issue?
I have to place another order for parts for a different car soon, so if I need anything for this LC I'd like to do it sooner than later
2001LC
SILVER Star
It may. But I suspect PO cleaned it.
First I don't have a clear picture of what and when VSC is coming on.
But I'd start with read codes.
Then identifying brake master leak point(s).
Is it blowing out just the cap, or cap and leaking from under the reservoir also.
To do this, I'd:
Properly top to max line, after 40 pump IG key off.
Place cap on properly.
Wash & dry master of all fluid.
Then have some pump brake pedal a few pumps with key on. Then pump pedal more aggressively. As you watch for leak.
If fluid blows out the top. Sure, try cleaning reservoir and replacing the 3 (2 sizes) grommets at bottom.
Note: There is a level detector inside the reservoir. Cleaning can damage. Hunt in mud, for what to clean with. IIRC guys are using alcohol.
2001LC
SILVER Star
I missed this.This may motor. If master puking fluid, leaking and motor running sporadic. Sound like a new master is needed.
Perhaps it best if we talk on the phone. Send me a DM (PM) with your phone number. I can talk in the AM around 6 to 8 AM MST
Thanks again for all your help. I bit the bullet and bought an entire new Brake Master Cylinder Assembly.
From the dealer I like to order from (Springhill Toyota of Mobile, AL), it was $1,430.24 with included shipping.
Very expensive but better than any other price I could find, even from Partsouq or Amayama.
I don't want to mess around with sudden loss of brakes, so the cost is justified.
Question: how many bottles of Toyota 12oz brake fluid should I buy? I also am going to replace all the rubber brake lines while I have the system opened up.
For anyone in the future reading, be sure to triple check the part number for the Master Cylinder Assembly.
My truck is an 2002 and there are two different part numbers that could apply, depending on build date.
Just call the dealer parts department and have them check, along with adding your VIN to the checkout field that asks for it, so you have recourse if you get the wrong thing.
Also watch out if you're ordering from a website like Partsouq because there is a part number for trucks without VSC and I'm not sure that any of our USDM trucks lacked VSC.
