ABS and Brake light on. What does it mean?


Asked by Feb 08, 2010 at 02:26 PM about the 2001 GMC Sierra 1500 SL Standard Cab LB

Question type: Maintenance & Repair

My abs light and my brake light is on, I heard this is a pretty common issue with these trucks. What
are some recommendations on a starting point for troubleshooting.

40 Answers

Matthew Huttema

I have the same thing on my truck. what year is yours? i got it checked out at the shop and they said that i would have to replace the abs computor which is about $2500 CDN

73 out of 73 people think this is helpful.
Sam Salameh

i had that same problem and all my car need was break fluid .. i guess thats the cars way of telling u you need break fluid !! hope it helps

25 out of 25 people think this is helpful.

In many cars and trucks, the abs sensor is built into the wheel bearings of each wheel. These thin wires can become corroded and break, especially if you live in the Northern states where road salt is a plenty in the winter. As the previous reply stated- check the fluid first. If all is good, you could contact a GM dealership and have them scan your system with a Tech2 scanner. That would be able to tell you exactly what wheel is causing the trouble and DTC. ( diagnostic trouble code). Or you could pull each wheel, disconnect the bearing harness, hook up a continuity tester to the two leads and spin the bearing. If the meter changes its reading, then that bearing is good. If it stays at 0, then the wire internally is broken, causing an open circuit, therefore causiung the ABS/brake light to illuminate. Good Luck

72 out of 72 people think this is helpful.
Glenn Clingenpeel

Mine sometimes comes on when I start the truck, and sometimes when I am moving at constant speeds. Sometimes, it can be a month or more, before seeing the light come on. I have read the wheel sensors may be dirty. How does one clean them? Does the wheel hub, or wheel sensor need to be diassembled, in order to clean it?

256 out of 256 people think this is helpful.
Josepi Locascio

what happen to mine was it came on and off and i hooked up the scanner and it said the speed sensor so i changed the wheel bearing and it fixed the problem

25 out of 25 people think this is helpful.

Im having a problem on my 2004 sierra where my abs light comes on when i hit bumps in the road. but then it will go away either on its own or when i turn the truck off and back on. this all started happening after i got my tires aligned. ive already replaced the front two wheel bearings this year as well

135 out of 135 people think this is helpful.
Bob Rae

KevDizz, that's the same thing that's happening to me except I never had the tires aligned. I replaced the sensor that the code came up for and still comes on and goes off when it wants to.

38 out of 38 people think this is helpful.
Jeremy Lancaster

Or could mean u need to change your brakes

14 out of 14 people think this is helpful.
Obey Cool

I have a question abs because it pop up my dashboard and I am driving a GMC ENVOY THE ON MY TRUCK IS A 2000 WHAT SHOULD I DO

100 out of 100 people think this is helpful.

I have a 2004 GMC Sierra Truck. The transfer case will not engage into four wheel drive. I took it to a GMC dealer and they are saying that is internal, but can not diagnois it until it is taken apart. Anyone have any suggestions?

34 out of 34 people think this is helpful.
Barbara Turner

I have a 98 Blazer. My husband just had the clock spring, both airbag sensors front driver and passenger replaced, vacuum hose, front sway bar, all front brakes - rotors, hub assemblies, calipers and that was just to get it inspected! Since I got it back however the abs light was coming on and off and the left front brakes would bddddtttt grab and make an awful ffflllllpppp sound and scare me to death. Took it to Auto Zone and the girl put the code diagnostic on it and showed me it was the left front brake with a code of 225 and 227, the speed sensor. Took it and got that fixed this morning and that fixed the braking problem but now the ABS light is on and won't go off at all. They told me that I needed to have the complete system diagnosed for all codes and wires, etc. could be bad or something wrong. HELP! Does anybody have any other cheaper ideas! I'm on full disability, my husband just laid out $1,500 to get all I talked about above fixed, I laid out $184.00 for the speed sensor. I'm being drained fast! WHAT could it be?! Thanks!

58 out of 58 people think this is helpful.
Bob Rae

I replaced the speed sensor and it still came on so then I ordered a new hub assembly which came with a speed sensor(didn't know that) so I put that on and haven't had a problem since, been about ten months now. Now I have an extra sensor. Wish I could help more, was yours a repairable or in a flood or something.

16 out of 16 people think this is helpful.
Barbara Turner

Loztcauze: My husband as I said in my post had all rotors, hub assys, calipers, ALL of it replaced brand new. No it was garage kept for the entire life of the vehicle prior to my purchase. It's in basically mint condition. Thanks anyway!

4 out of 4 people think this is helpful.

the cause for the abs light and brake light to come on is because of your master cylinder is on its way out i had it happen on my truck replaced the master cylinder and the lights have not come back on it common for this to happen if had to replace it in a couple of vehicles of mine the are gm modeled vehicles

15 out of 15 people think this is helpful.
Barbara Turner

@ jessegm1991 - Actually, my husband who used to build cars and was 1 year away from rookie NASCAR status when we married checked all around my Blazer and the MC was and is fine! What it turns out to be is simply an open circuit when I had the codes checked. So thanks for your expertise.

3 out of 3 people think this is helpful.

ok that something i looked into before i replaced it there wasnt open circuit it was bad but i also found out that my hub is bad everything in it it hasnt been replaced im doing that today

1 out of 1 people think this is helpful.
Barbara Turner

Are you talking about the ABS computer unit, those run about $300.00 where I live. Everything works fine but just the abs light on. It passed inspection and they told me not to worry about it. The ABS brake sys works fine, stops on a dime.

4 out of 4 people think this is helpful.
Seth Hartman

could a wheel speed sensor being disconnected during an alignment cause it to pull to one side? 97 GMC Yukon

15 out of 15 people think this is helpful.
Ken Copeland

I have a 2000 GMC Sierra 1500 with the ABS lights on also. Truck runs like a dream. I was told it was the E break line. IDK if that's true or not at this point but it has been to 6 states repeatedly in the last 3 years & ZERO issues. On a side note my friend just bought a 2001 GMC (same truck & same lights) still runs like a dream also... IDK if the lights are more than just annoying inconvenience that GM triggers to get more $$$... Neither of the trucks seem to have any REAL issues.

15 out of 15 people think this is helpful.

My abs lite came on turns out I needed new brakes which I got abs lite still on does it have to be reset .

49 out of 49 people think this is helpful.
Derek Feeback

I'm having some trouble on my 04 saturn vue ... The ABS light the emergency brakes light my traction control light and the service car light comes on and all my gags stop working , at some point my gags will work but most of the time it won't .. Anyone know what can be the main issue

7 out of 7 people think this is helpful.
Ivan Cruz

Ecm modul ground wire,, clean it and put it back ,, when ligth turn on and off , it make no good ground, and sometimes it does

11 out of 11 people think this is helpful.
Steve Boyd

Lol i removed the bulbs. Ahh thats better and i didnt even spend a penny

7 out of 7 people think this is helpful.
Maris Mitchell

Ok, so after reading all posts, I'm similar with abs and emergency light coming on every few starts after having front end aligned. It causes the cruise control to be inop. Had brake pads changed all the way around and mc had plenty of fluid. My question is how can you tell if mc is good, and if car needs reset? Reason I ask is when sensor said I needed an oil change, after having the service done, it still displays the need oil change message. Been a chevy driver a long time but first time dealing with all the bells and whistles of my recently purchased 2004 z71 tahoe

12 out of 12 people think this is helpful.
Maris Mitchell

Reset the system. Cured my messages

14 out of 14 people think this is helpful.
Barbara Turner

@ Maris: Exactly how do you "reset the system"? Do I have to be a mechanic to do that? Which I am not, btw

31 out of 31 people think this is helpful.
Maris Mitchell

Go to a shop with a diagnostic reader and ask them to. Best 40-60 bucks you'll spend. But ask them to read it first. :) case there's something going on you should be aware of

5 out of 5 people think this is helpful.
Barbara Turner

Right after I had the speed sensor replaced last year when the ABS light came on when I start it up and it won't go off, I took it to Advance Auto and the code came up that it was an open circuit. Should I still take it for what you suggest when I already had that read? The brake light goes off as it's supposed to. Just the ABS light remains on. I was told that it being on would not affect my getting it inspected as long as the brakes work fine. I'm not thinking it's anything but just the circuit broken somewhere because when I slam on the brakes, it stops straight on a dime. Our family Master Mechanic told me not to worry about it because as long as the brakes are functioning properly, it means the ABS is functioning properly. He checked everything. He couldn't figure out what the code indicated as well.

3 out of 3 people think this is helpful.

There is nothing mechanically wrong with your GMC truck. This is a GM engineered ploy to get you to take your vehicle to the dealer for a remedy. I did and it cost $45 and a tolerance of morons at the dealer telling me there was "water" in the fuse box? I paid the bill, started the truck and the ABS light and ding dong came on as it had before. 2 years later it is still coming on about every other time I start the truck! With 33,000 city miles on it, the ABS has never been used since I do not drive on the interstate for longer than 10 miles. Gotta love GM, they'll try anything to scare the customer into giving them more business!

7 out of 7 people think this is helpful.
Angel Perez

Same here. My ABS ligjt comes on. I have a 99 chevy silverado 2500 4x4 6.0. What could i do to take that off?

17 out of 17 people think this is helpful.

To all with this problem NHTSA issued a recall on most of these vehicles. Recall #05V379000 contact GMC @ 866-996-9463 or GM @ 800-630-2438

13 out of 13 people think this is helpful.

Unfortunately for those of us with pickups earlier than year model 1999, the NHTSA recall doesn't include. To be more specific, the recall is for years 1999-2002.

7 out of 7 people think this is helpful.

I own a 03 Yukon XL and this light keeps coming on ...check ABS stystem....but i have had my brake system checked and all was fine, light keeps popping on and then we unplugged batter thinking that it needed a reset and it stopped for like 3-4 days then here is comes again.....I want to take to the dealer usually i trust them but after reading these responses above not sure what to do?

3 out of 3 people think this is helpful.
Daddyos Marine

Guy on youtube showed a ground wire screws that bolts in to near the radiator firewall on the driver side. That might be a ground for the abs module that gets corroded and causes the intermitant problem just like a loose battery cable would.

2 out of 2 people think this is helpful.
Rowan Perkins

The ABS and brake light came on in my 2005 vue. I pulled all the wheels, brakes looked fine and topped off mc. There was a lot of rust on the front rotors - that may be flaking off onto the sensor pickup. About a week later the brakes started grabbing. I pulled the small abs fuse, no change. Pulled the big 40 abs fuse, brakes no longer grab/drag. AZ couldn't find a brake code. I'll try AA today. May just replace rotors just to be sure.


ABS light will come on if brake fluid is low, sensor is on the fender side of the master cylinder but otherwise 20% broken wheel speed sensor wire or just corroded and making a bad ground where the bolt holds it to the hub. 80% of the time it's a bad speed sensor , either way you have to remove the brake caliper and rotor to get to the sensor. Remove the sensor, clean the area around the hole it goes into and blow it out with air then replace the sensor. If you have a good diagnostic tester it will tell you which side is bad Left or right. Replace, then reset the dtc code and your good to go. Once in a great while it will be one of the expensive ABS electronic components but if you aren't sure get a second opinion unless you just like throwing your money away. The free test they do at most auto parts stores they do with a $30 code reader which won't properly identify the problem. Also you need to clear the trouble codes and retest, sometimes they old codes stored in the ECM that were never cleared after repairs were done.

3 out of 3 people think this is helpful.

Heres a good one i jave a 2011 chevy silverado 1500 my stability/traction control lights have been going nutts lately comeing on and off but when the (service stability track light) comes on so does the (ABS) light....well it did that for a week or so, and got worse! now its on 90% of the time and when i start it up it wont be on i put my foot on the break to shift and they both pop on and my truck will not shift out of park!! I literally have to keep my foot in the break reach down under the dash finth the wiring harness that goes to the break unplug it, WITH FOOTBON BREAK STILL shift the truck out of park to drive then plug it back in, But my break lights DONT WORK they are on but when i step on the break the flash brighter then go back to running lights.......the abs light goes out untill i plug it back in!!! I think the NOT SHIFTING part has to do with the neutral safety switch or the truck not recognizing that the break is applied...i had someone tell me that its the modual, and i had someone tell me its a selanoid sorry for the terrible spelling but can anyone help me and give me some ideas and were to look for this problem pos chevy that i paid way to much for! Or a beer can basicly!! Thanks justin

2 out of 2 people think this is helpful.

I have a 04 mercury grand marquis my abs and brake lights are on they did all testing but could not come up with anything but one test came up with code 1445 some thinks my be master cylinder could that be master cylinder for both lights to be on same time

Donnie Longo Jr.

Someone Just Said That There Is A Recall 99' & Up On The Abs Lights Coming On, Mine Is A 99' Late 99' Chevy Silverado LS 2500 6.0 V8 Crew Cab Long Bed, & The Abs & Brake Light Is On, & I'm Being Told Its The Abs Module Underneath The Drivers Side Frame Rail, Is This Recall True & Are They Gone To Fix It & Who Do I Call? Donnie South New Jersey

3 out of 3 people think this is helpful.

The master cylinder has two separate circuits front to rear. When one circuit has a fault the other circuit remains working. If a circuit faults it is usually due to a sustantial loss of brake fluid or a leak. This signals the abs and brake lights on vontrol panel to illuminate bright.

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