5 Causes of an ABS Light to Come On (and What to Do)

(Updated on May 29, 2020)

Modern vehicles have what is known as an anti-lock braking system. The purpose of this system is to keep the driver safe by preventing the wheels from locking up as you apply the brakes. That way, you can keep control over the steering and your vehicle won’t skid as a result of the wheels locking up.

In addition, there is a warning light on the dashboard which will illuminate if there is any sort of problem with the anti-lock braking system. This is a light that you need to take seriously because it is an early warning sign that your braking system needs to be inspected right away.

5 Common Reasons the ABS Light Comes On

There are many causes which could make an ABS light come on. It doesn’t always mean there is a problem with the anti-lock braking system directly. There could also be a problem with other sensors or components that it communicates with as well.

Below are the top 5 causes of an ABS light coming on.

1) Low Brake Fluid

low brake fluid

The brake fluid has a lot to do with controlling the braking pressure within an anti-lock braking system. There is a brake fluid reservoir which holds the fluid of the anti-lock braking system.

Sometimes there could be a leak from this reservoir which will cause the fluid levels to drop. Either that or excessive amounts of air may exist within the system.

Either way, it may certainly cause the ABS warning light to illuminate on the dashboard.

2) Faulty Speed Sensor

bad speed sensor

There are speed sensors built into every wheel’s hub which calculate the movement rate of that wheel. This information then gets transmitted to the anti-lock braking system.

If it turns out that at least one of the wheels is moving too slowly, the anti-lock braking system will increase the pressure of the brake fluid to allow the wheel to move at a normal speed.

But if there is a problem with the speed sensor, the anti-lock braking system will detect that and cause the warning light to illuminate on the dashboard.

Read also: 5 Symptoms of a Bad Intermediate Steering Shaft and Replacement Cost

3) Bad ABS Module

bad ABS module

The module of the anti-lock braking system can form corrosion after a while. This is actually one of the most common reasons for why there ends up being a problem with the anti-lock braking system.

If the module is corroded, then it can’t obtain information from the wheel speed sensor. As a result, the ABS light illuminates on the dashboard. It doesn’t even take a lot of corrosion to cause this to happen either. But you will need to replace the module after this happens.

4) Bulb Check

dashboard warning lights

Some vehicles will perform what is known as a bulb check on the dashboard. This check is for the driver’s convenience, so they know the bulbs of their vehicle’s warning lights are working properly.

These lights will usually turn off by themselves after a certain amount of time. In some instances, there may be a glitch in the bulb check which keeps the ABS warning light illuminated after the bulb check is completed.

5) Worn Hydraulic Pump

bad ABS pump

If there is one wheel of a vehicle that moves at a different speed than the other wheels, the wheel speed sensor detects this and then notifies the anti-lock braking system.

Once this happens, the system will activate the hydraulic pump to increase the amount of brake fluid pressure. This will allow the wheels to maintain their traction as they’re touching the ground.

Unfortunately, hydraulic pumps tend to get worn out after years of using them. This would certainly cause the ABS light to come on, which means you’d need to replace the pump right away.

What to Do When the Car ABS Light Comes on

When the ABS light activates on your car’s dashboard, it signals that something is wrong with the anti-lock braking system. That means if you need to step on the brake pedal quickly to stop your vehicle, then it might not stop as fast as you want it to. As a result, you could end up in a serious car accident.

Basically, the function of the anti-lock braking system is to keep your vehicle’s tires on the road as you aggressively step on the brake. That way, the wheels don’t lock up or skid uncontrollably on the road during the braking process. This is particularly important if the road is slippery or wet.

There are different reasons for why the car ABS light would come on. The main reason is from simply turning on your vehicle. After you put your key in the ignition and turn it on, the computer does a test on the anti-lock braking system to ensure it is functioning normally.

If the computer doesn’t find a problem, the ABS light will turn off quickly. But if the ABS light stays on, it means there is a problem with your anti-lock braking system.

Sometimes you might be driving, and the ABS light will suddenly come on too. In any case, you need to bring your vehicle to an auto mechanic whenever you experience this issue.

They are the only ones equipped to diagnosing the issue and turning which component of the anti-lock braking system needs repair or replacement.

Can You Drive Your Car With the ABS Light On?

Just because your ABS light is on, that doesn’t mean you can’t drive your vehicle. In fact, you will still be able to step on the brake pedal and slow the vehicle down.

However, your ability to perform a panic stop will be limited as you run the risk of locking the tires under heavy braking. Locking the tires increases stopping distance dramatically and prevents you from steering until the front tires regain traction.

What you need to do is drive carefully to the nearest mechanic after the ABS light comes on. Brake slowly when necessary but avoid braking quickly or aggressively. If you can do that, then everything will be fine.

The only circumstance where you shouldn’t even attempt to drive your vehicle is if the brake system light comes on when the ABS light is on. The brake system light indicates a much bigger issue with your braking system — a problem which may limit your ability to brake the vehicle at all. Therefore, you would need your vehicle towed to the mechanic if you notice both lights on.

93 thoughts on “5 Causes of an ABS Light to Come On (and What to Do)”

  1. I am deicing Toyota yaris 2009 model. ABS and handbrake light stays on and speedo also not working since I had my front wheel bearings replaced. Took vehicle to Toyota. They replaced both speed sensors. Drove the vehicle for about 30 Kilometres and the same problem came back. Please advise.

    Reply
  2. My 1997 Toyota 4Runner light comes on and sometimes the battery light too, the battery light goes off but ABS light doesn’t. I can pump the little cap on brake fluid and it seems to correct the problem, then later in the week the ABS light pops back on ??

    Reply
    • Perhaps you have an air bubble in the ABS module. I’m not exactly sure what’s going on but I’d either get it checked out at a shop or do some digging yourself if you feel comfortable doing your own diagnostic work. I don’t know if the ABS light coming on is related to the battery light coming on. You’ll have to do a bit of testing to figure that out.

      Reply
  3. I have 2013 Toyota Corolla LE. Alternator changed 2 years back and alternator belt changed 1 year ago. Now all of a sudden the battery light came. Changed battery, but still the battery light is on. Drove around 300 miles with battery light on. Now the ABS and steering and battery lights are on dashboard. Any suggestions?

    Reply
    • Check your grounds. Make sure all ground straps are clean and tight. If you look at a wiring diagram, you may find a common ground that affects the ABS, steering, and battery. It could even be the main ground off the battery that’s causing the issue, but you’ll have to do some testing to know for sure.

      Reply
  4. We just bought my daughter a 2010 Nissan Sentra SR. Brakes are great and good shape, had the local mechanic check it out. Took it out for a drive after being “checked out” by the mechanic and around 60-65mph the brake/abs lights come on. Once the car is stopped and shut off and back on, those lights are no longer on. They do not come on until the speed reaches a little over 60mph and stays at that speed for several miles. Otherwise those lights never come on. Any ideas? I assume one of the speed sensors is bad/dirty and I plan to go and get a scanner that reads ABS but thought I would start here first.

    Reply
  5. Over the last year, my ABS light has come on and is usually joined by the TRAC OFF Light. This is supposed to be normal for TRACtion systems…BUT!!! The TRAC OFF light is FLASHING!! I looked up flashing TRAC OFF light – there is no Flashing detailed in the manuals – just solid ON. Part of the time the TRAC OFF light would start to flash a few seconds after the car has been in motion (almost at time door locks automatically lock on motion). Sometimes the ABS lights up but sometimes not???
    Not in manual AND no codes are sent to diagnostic modules (if used).
    Not a good time to find a mechanic during COVID times.

    Reply
  6. Hi Not sure if you have managed to fix the problem. Am driving the same car make and had the same problem where everything couldn’t function on the panel. Only to find out, the mechanic fitted the bearings the other way around, so it couldn’t sense anything. I had to replace them again to have the panel function normal.

    Reply
    • It’s possible. A different tread compound, tire diameter, or tread depth could affect the way your ABS system is able to brake. Your owner’s manual may have additional info for your specific vehicle.

      Reply
  7. I just got an’07 Ford Edge. The abs light stays on as well as the Trac light and when I’m braking, there is a very loud scratching noise. Any ideas what the problem might be?

    Reply
  8. I have a 2004 Chevrolet Trailblazer LT. We just replaced brake pads all the way around, and also one of the calipers on one of the front wheels. My ABS light had been coming on and going off for some, and check engine light has been coming on and staying on, or it will be constantly flashing. Sometimes the cruise control will work, and then again it won’t. But I thought for sure that the ABS light would stay off, after replacing all the brake pads. And as far as the check engine light goes, I know what the problem is there also. I have the number 6 engine coil needs to be replaced. this has been a problem for some time, but the vehicle sat for almost 9 months without being driven because of my vision. Will see once what happens after that ignition coil is replaced.

    I also am aware of that wheel speed sensor. But like I stated it could be, because of the engine only operating on 5 cylinders instead of the 6.

    My tires are all the same, as they are all new, and the same brand and everything.

    Reply
  9. I have a 2001 GMC Sierra and had a situation where both my ABS and brake lights would turn on and stay on all the time. After checking it with a code reader I changed out the ABS control module as that’s what the code and multiple videos on the internet told me to do. Now the ABS and brake lights will turn on simultaneously then the ABS light will turn off followed by the brake light…then both turn on and this continues for a very long period of time. When I slam on my brakes the ABS does not engage. Thoughts?

    Reply
    • This is a common issue on first generation Sierras and Silverados. Often the problem is the ABS control module, but sometimes it’s just a bad ground. There’s a ground on the driver’s side of the frame used by the ABS module that is particularly susceptible to dirt and corrosion. Make sure this ground is clean and tight.

      If you bought a refurbished ABS module, there’s always a possibility that your replacement is bad. If you still have your old module and are handy with a soldering iron, I’d find a video on which connections need to be soldered and give it a go.

      Reply
  10. 2002 Silverado: My problem is the abs light will stay on after I start the truck. When I reach the speed of 7-8 mph, the light will disappear, but then whenever I brake in traffic, stop light, etc, the light will come on for about 1-2 seconds, turn off (as I’m still pushing the brake pedal) and works properly (I’ve tested it on or slippery roads).

    Reply
    • Check your brake fluid, make sure that’s topped off.

      02 Silverados were affected with a poor connection in the ABS module, which could be the root cause in your case. Sometimes the issue stems from the module itself, sometimes it’s a dirty or corroded ground. If the problem is with the module, you may be able to open the module and re-solder it yourself instead of replacing it entirely. If the problem is a bad ground, it’s likely the one on the driver’s side frame next to the ABS module.

      Reply
  11. I have a Hyundai Grand i10 automatic, 2016 module. I have been having problems with the ABS sensor snapping. I have taken it to the service provider and they insist that a rat is snapping the wiring of the sensor. My argument is would a rat nimble on the same sensor four times. On the fourth repair, while I started the vehicle the ABS light did not disappear after idling it for 15 minutes. I will be taking it back tomorrow and I am not sure what their response I will receive. in the mean time I have been fitting the bill for all replacements or repairs to the sensor. Currently while driving the vehicle until my appointment I experience a popping sound when I use the brake and a rattling noise when I turn the vehicle towards the right. Your advise is greatly appreciated.

    Reply
    • It sounds like there may be something else going on that’s causing the popping, but I don’t know what that could be. It wouldn’t hurt to get a second opinion if you’re concerned the service provider isn’t diagnosing the problem correctly.

      Reply
  12. I’ve had it happen in extreme cold below 15’ in my F250 goes away when warm temps return. In those temps it usually involves snow and ice so I wonder if the sensors may be acting up . Also in those situations I’m in 4HI which may contribute. I’m no mechanic just guessing.
    Anyone know if either of those conditions could cause it, just wondering?
    Thx

    Reply
  13. I occasionally get my abs light with a message “turn slowly to calibrate” and all my guages turn off. The Lincon Navigator defaults to 3rd and it kills my battery. Once I jump it it’s OK. It charges and holds charge, just have to reset my air suspension which turns off.
    The only code is once the guaged stop working is for discharge. I have 14v till then.
    I can’t find any issues in the ABS or why when this occurs it says “turn slowly to calculate ” ABS or the compass won’t default the trans to 3rd and kill the guages and charging system?

    Reply
  14. Have a 2008 F150. Power steering went out and a chain store oil change place replaced the pump. The ABS light has been ever since. They have been unsuccessful in trying to find why. I don’t think it it is just a coincidence that the lights came on when they replaced the power steering pump. What are my options?

    Reply
    • Sounds like it may be a wiring issue or a bad ground. Perhaps they forgot to plug something in or a wire was broken during the installation. You’ll have to do a bit of diag to find out for sure.

      Reply
  15. Today the ABS and Traction Stability lights on my 2013 Nissan Maxima went on after traveling 150+ miles. I parked the vehicle at my destination, light still on. Four hours later, I started vehicle to drive back home and the ABS, Traction Stability, Tire, and Brake lights went on. And, the Speedometer and Odometer ceased to work. Brakes seemed to function fine, but it made the 150+ mile trip somewhat concerning, Any idea what may have caused this to happen? Thanks, Phil

    Reply
    • Sounds like a speed sensor has quit working. You’ll have to check the factory service manual or a repair manual to see which sensor(s) give a signal to the speedometer and odometer, then work backwards to determine if the fault is with the sensor itself or the wiring.

      Reply
  16. I changed the evaporator in my 2011 toyota hilux and shorlty after my ABS light came on and stayed on. Parts of the dash board had to be removed to acheive this. Is there a possibility that something was not reinstalled correctly in that space that could have lead to the light coming on?

    Thanks, Nathaniel

    Reply
  17. I had no Indication of a brake problem , no brake warning light coming on, no abs light coming on. But, When I took it to the dealer for a recall problem and a key fob problem the dealer said my master cyl was bad and then said the bad abs module was what wore the master cyl. out and both needed to be replaced for about 2 grand . Was i just taken to the cleaners or what?

    Reply
  18. Good morning,my Honda civic 2006 is giving problem,D driving signal is blinking what is the cause,but the car is moving fine

    Reply

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