Brake Failure & ABS/Brake light on dash with alarm? (1 Viewer)

[Kayphix]

Yesterday in rainy Denver, my ABS and Brake light on the dash turned on with the alarm sounding. About 2 minutes later, my brakes went out. Luckily was in a parking lot.

I thought I prepped to avoid this when I paid to get a new Brake Accumulator and Master Cylinder (new). The rear also got new calipers, rotors, & pads.

This morning I took it to a shop at 3AM (2mi away) who did the work to get it checked out when they open. Brakes started working and alarm turned off.

No codes were given, at least with my crappy OBDII reader. I will still have them look at it. Anything I should maybe have them check out?

Thanks all.

 

[excessive]

Common problem - its your brake booster / accumulator motor going out. You can replace just the accumulator motor (not sold by Toyota )
check this thread for lots more info

Poll on total brake failure in 100 series

There is some discussion going on of total and sudden braking failure in 100 series models, with reports of no -or essentially no- braking left at all a very short time (of the order of seconds/minutes) after dashboard warnings. That is scary stuff. It is, however, also difficult to find out...

forum.ih8mud.com

 

[Kayphix]

Common problem - its your brake booster / accumulator motor going out. You can replace just the accumulator motor (not sold by Toyota )
check this thread for lots more info

Poll on total brake failure in 100 series

There is some discussion going on of total and sudden braking failure in 100 series models, with reports of no -or essentially no- braking left at all a very short time (of the order of seconds/minutes) after dashboard warnings. That is scary stuff. It is, however, also difficult to find out...

forum.ih8mud.com

Yea, it must be a bad one then. It's brand new from 2,000mi ago! Haha.

 

[2001LC]

When you say "brakes went out". Did pedal go to the floor?
Have you checked fluid level? (Read how to, on the brake masters reservoir)


Where a new brake master with booster assembly, could be defective. It would be first I've heard of.
If for some reason booster motor is running prolonged periods. This could prematurely wear out motors commutator. When this happens brakes can work, then not then work again. A leak in the systems or air could result in excessive long run times also.

 

[Kayphix]

When you say "brakes went out". Did pedal go to the floor?
Have you checked fluid level? (Read how to, on the brake masters reservoir)


Where a new brake master with booster assembly, could be defective. It would be first I've heard of.
If for some reason booster motor is running prolonged periods. This could prematurely wear out motors commutator. When this happens brakes can work, then not then work again. A leak in the systems or air could result in excessive long run times also.

The alarm went off, about 2 minutes later, I couldn't stop the vehicle as I pressed the brake to the floor. It didn't stop until I pulled the parking brake hard.

I left it until next morning, drove it without traffic on the roads at 3AM, codes on the dash, alarm still blaring, however I had brakes again (thinking I was gonna limp my way two miles with the e-brake). Alarm went off, codes went away, I had brakes and parked it at the shop. Super odd.

Fluid in the reservoir looked full and clear. Could be a leak somewhere else. Definitely something for them to check out.

Appreciate it!

 

[Kayphix]

So, got a call from the mechanic. Apparently my 'ABS Motor is failing'. Is this not what the master cylinder/brake accumulator is? Can anyone identify which part this is with a photo?

 

[Kayphix]

So, got a call from the mechanic. Apparently my 'ABS Motor is failing'. Is this not what the master cylinder/brake accumulator is? Can anyone identify which part this is with a photo?

Nevermind. I think I found it. Searching the spec book, I thought I replaced all those 'necessary parts' as apart of a set, but nope. Think I skipped the Booster Pump Motor. Sad day!

 

[medtro]

Nevermind. I think I found it. Searching the spec book, I thought I replaced all those 'necessary parts' as apart of a set, but nope. Think I skipped the Booster Pump Motor. Sad day!

What was replaced 2000 miles ago?

 

[Kayphix]

What was replaced 2000 miles ago?

I do not think it included the Booster Pump Motor (BR-49 of the spec-book). That is hindsight 20/20 on my part for trying to do something retroactively and not doing more research.

They just replaced the master cylinder and accumulator. I assumed it all came as a kit.

 

[Kayphix]

I do not think it included the Booster Pump Motor (BR-49 of the spec-book). That is hindsight 20/20 on my part for trying to do something retroactively and not doing more research. I basically went in telling them as a safety precaution (approached 250k miles), to replace the master cylinder/accumulator to avoid brake issues.

They just replaced the master cylinder and accumulator. I assumed it all came as a kit.

 

[2001LC]

So, got a call from the mechanic. Apparently my 'ABS Motor is failing'. Is this not what the master cylinder/brake accumulator is? Can anyone identify which part this is with a photo?

If motor fails, pump can not build booster pressure in the accumulator. Accumulator, stores the pressure. Stored pressure is released to assist braking when pedal pressed.

ABS "motor" is not actually a part/term. The "motor" is called booster motor. It is the number one part that fails, resulting in sudden brake failure.

ABS unit is the black box on side of master and is only sold with master. The ABS system also has it's own CPU, which under the dash.

Nevermind. I think I found it. Searching the spec book, I thought I replaced all those 'necessary parts' as apart of a set, but nope. Think I skipped the Booster Pump Motor. Sad day!

You likely purchased just brake master. The whole assembly, is called: booster assembly with master.

I do not think it included the Booster Pump Motor (BR-49 of the spec-book). That is hindsight 20/20 on my part for trying to do something retroactively and not doing more research.

They just replaced the master cylinder and accumulator. I assumed it all came as a kit.

They likely only replaced the master.
Toyota sells:

1. Master.
2. Accumulator.
3. Booster motor w/pump
4. Booster assemble (motor, pump & accumulator).
5. Booster assembly w/master.

 

[Kayphix]

If motor fails, pump can not build booster pressure in the accumulator. Accumulator, stores the pressure. Stored pressure is released to assist braking when pedal pressed.

ABS "motor" is not actually a part/term. The "motor" is called booster motor. It is the number one part that fails, resulting in sudden brake failure.

ABS unit is the black box on side of master and is only sold with master. The ABS system also has it's own CPU, which under the dash.

You likely purchased just brake master. The whole assembly, is called: booster assembly with master.

They likely only replaced the master.
Toyota sells:

1. Master.
2. Accumulator.
3. Booster motor w/pump
4. Booster assemble (motor, pump & accumulator).
5. Booster assembly w/master.

Yup, you are correct. Hindsight 20/20. Meant to replace it all at the time but just replaced No. 1 & 2. Probably would've saved a tiny bit of money doing it all at once, but what can I do. Just glad I was able to get it stopped without incident! Thanks!

 

[BigBlue84]

I have the same ABS/Break lights on with alart tone fault code C1 1252 and C1 1256 also a IG Voltage low message I have a MC unit on the way any other issue I maybe missing? 1998 LC

 

[2001LC]

I have the same ABS/Break lights on with alart tone fault code C1 1252 and C1 1256 also a IG Voltage low message I have a MC unit on the way any other issue I maybe missing? 1998 LCView attachment 3419459

I'd make sure I've good battery, with minimum of 12.5V. Then clear codes and see what comes back.

 

[BigBlue84]

I'd make sure I've good battery, with minimum of 12.5V. Then clear codes and see what comes back.

Battery good at 14v, released connects and released pressure on accumulator, cleared codes, fluid level increased as expected. Connections reconned, key to on. No ABS/BREAK until pump stopped and started ¾ times, codes now returning. ABS/BREAK lights on
C0278,C1252,C1253,C1254,C1256.

 

[2001LC]

Battery good at 14v, released connects which connection? and released pressure I assume by pumping brake pedal key off 40 times? on accumulator, cleared codes, fluid level increased as you pumped pedal key off? as expected. Connections reconned, key to on. No ABS/BREAK until pump stopped How long until pump stop once key on? and started ¾ times, codes now returning. ABS/BREAK lights on
C0278,C1252,C1253,C1254,C1256.

 

[BigBlue84]

EM1 and EM2 to check continuity per DI-264, Key off correct, pump runs for about 30/40 seconds cuts off and about 5 second back on. off 5 second then back on. Repeats and the the lights come on and the 5 second cycle continues

 

[2001LC]

Sound like a pressure leak. New Master is the cure.

 

[BigBlue84]

Sound like a pressure leak. New Master is the cure.

Have it on order. Just checking and thank you for the validation of findings

 

[2001LC]

This may help further validate:

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...

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