If you are like most people, you never think about all the hundreds of safety features, such as the stability system, anti-lock brake system, or vehicle warning lights. So, when you’re driving down the road, the last thing you expect is the ESP BAS light suddenly popping up on your dashboard. And although it may seem like your vehicle is fine, you never want to ignore this warning light.
If the ESP BAS light comes on, it indicates a problem with your vehicle’s Electronic Stability Programme (ESP) or the Brake Assist System (BAS). The most common causes for this light includes uncalibrated/bad steering angle sensor, bad wheel speed sensors, a bad brake switch, wiring issues, or other braking problems.
So, if you want to know more about the ESP BAS light, what to do if it comes on, and how to fix it, we have all the answers and more for you here. Keep reading!
What are ESP and BAS?
There are many warning lights on a car’s dashboard, and it can be difficult to remember what each one represents. So, before we dive into what would cause the ESP BAS warning light to come on, I would like to briefly go through what ESP and BAS are and what this light means.
Electronic Stability Programme (ESP) is a computerized safety system, also known as Electronic- or Dynamic Stability Control system. It’s designed to improve and maintain the stability and control of your vehicle by detecting and reducing loss of traction when slipping or during sudden maneuvering, increasing vehicle safety.
For example, let’s say you’re driving on snow, ice, or other slippery surfaces, and your car starts to slip. Whenever your electronic stability program notices a loss of traction, it will automatically apply the brakes on individual wheels and adjust the engine power to help keep your vehicle stable and steer more effectively.
Brake Assist System (BAS) is a safety braking technology that increases the braking pressure when the driver fails to brake with enough force during a potential emergency.
By identifying and interpreting the speed, intensity, and force with which the brake pedal is pushed down, the bas systems detects if the driver is trying to make an emergency stop.
If the brake pedal is not fully applied, the system overrides and applies full braking until the anti-lock braking system (ABS) takes over to prevent the wheels from locking.
ESP BAS light Meaning & Function
Just like the ABS and Traction Control light, there are two different scenarios where the light may be on. It can either be flashing, which means the ESP and BAS systems are active and engaging when it detects loss of traction or an emergency brake.
The second scenario is that the light can be solid, and the light won’t turn off, which probably is why you’re here reading about ESP BAS light.
The ESP BAS light will illuminate when it indicates a problem with the electronic stability program or the brake assist system. This light is just like any other of your vehicle’s dashboard warning lights, notifying you of a problem that may require repair.
ESP BAS Light Causes
The light comes on in response to various problems, ranging from minor repairs to more severe ones. That is why it’s never a good idea to blindfolded start replacing parts.
But the good news is, we’ve listed the most common causes, and together with an OBD reader (also called a diagnostic scanner or scan tool), you’ll likely be able to tell what problem you are dealing with.
1. Bad Steering Angle Sensor
Vehicles today have hundreds of sensors monitoring and collecting data to perform various safety functions, and the steering angle sensor is one of them.
The steering angle sensor (SAS) is responsible for measuring the angle of the steering input and how fast the steering wheel is being turned. With this data, the ESC module can then determine where the driver wants to steer and ensure the steering wheel is accurate and matches the car’s wheels.
When the ESP BAS Light comes on, the most common cause is the steering angle sensor needing to be replaced or reset. Hopefully, it only needs recalibration, but many times it’s also because the sensor has completely failed, so you’ll need to replace it.
Both are, however, quite easy fixes. To turn off the ESP BAS light by resetting the steering angle sensor, simply turn the steering wheel to the center, twice until it locks to the right, twice until it locks to the left, and back to the center. Your steering angle system should have been reset, and the ESP BAS light should turn off.
The process may be a little different depending on the type and model of your car; check your car owner’s manual to find out how to reset on your specific car.
But to replace the steering angle sensor, you’ll need to remove the airbag from the steering wheel, which is a serious problem as it can cause the airbag to detonate. So it might be a better idea to let a professional take a look at it.
To replace the sensor, first, make sure to unplug the battery. Next, remove the airbag. To do so, you must push the clip located on the back of the wheel. Then lock the steering wheel in the center and mark the wheel’s position. Use a socket and ratchet to remove the steering main nut. Next, remove the clock spring, and you’ll now see the sensor. Replace it and put everything back together. But for the ESP BAS light to turn off, you may need to re-calibrate the system.
A steering angle sensor usually costs between $120 and $250, and the labor costs average at $80 to $250.
2. Bad Wheel Speed Sensor
The wheel speed sensor is another advanced sensor you’ll find in every modern vehicle.
Wheel speed sensors are located at each wheel and measure and monitor how fast the wheels are moving. With the help of theses sensors, the ESP BAS system can collect and process data to tell if traction has been lost, so it can engage and help you maintain control of the car.
As you lose traction, the ESP BAS Light can come on as the system activates. However, the light should go off when the situation is resolved.
But if any of these sensors are not working properly, the ESP BAS light will likely stay on, but the warning light can illuminate your dashboard at any time if the ESP BAS system indicates a problem with the wheel speed sensors.
Replacing a defective wheel speed sensor is relatively simple. But sometimes, it can become stuck by rust, which can be frustrating.
To replace the sensor, jack up your car and remove the wheel where the bad speed sensor is. The sensor is located behind the braking discs. Remove the old sensor and put the new one in place.
If you are considering taking your car to a professional, the average cost to replace a wheel speed sensor is around $250. The good news is that about $100 to $150 of this cost comes down to labor. That means if you don’t mind doing the work, you can get the cost down to between $100 and $150.
3. Bad Brake Switch
The brake switch, also frequently known as brake sensor or brake light switch, is an electrical switch that is a part of the pedal assembly. When you want to slow down, and you push down the brake pedal, this switch will tell the rear brake lights to come on and alert people behind you that you are braking.
And although the brake switch is supposed to last forever, there’s a chance it can fail. And if it does, one of the symptoms of a defective brake switch is illuminated ESP BAS dashboard lights. A few other symptoms of a failed brake switch are trouble starting the car, malfunctioning brake lights, or issues moving the gear selector.
Unlike some other sensors, replacing a brake switch sensor is inexpensive; you can expect to pay around $35 to $75 for the part.
To replace it, find the brake switch sensor located above the brake pedal. Unplug the old sensor and put the new one back in. If the ESP BAS light is still illuminating, you might need to reset any trouble codes with an OBD2 scanner.
4. Wiring Issues
Your car is full of wires connecting electrical components together, and there is no difference between the different sensors and the control module.
And with the ABS wheel speed sensor located in the wheel housing, close to the tire, brake pads, and rotors, the wiring and connectors sometimes get damaged.
However, this is not very common since in modern cars, wires are often much better protected with sealing and weatherproofing around those areas. However, the occasional pothole or harsh driving can still cause damage.
Finding a wiring issue is one of the more difficult things to do when troubleshooting the cause, especially if you’re inexperienced. It’s also hard to determine the cost of fixing this problem; it depends on where the damage is and the extent of the work.
5. Worn Brake Pads and Rotors
While worn-out brake pads, warped rotors, or calipers aren’t typically going to be the reason why your ESP BAS Light comes on, it does happen, so we can’t rule it out completely.
But whether or not the ESP BAS light is on because of your worn-out brake pads or other braking components, you’ll want to keep your brakes in good condition with routine maintenance. Otherwise, your brakes may not be able to stop your vehicle when you find yourself in a situation where you suddenly need to brake.
If you’re taking your vehicle to a professional repair shop for new brake pads and rotors, you should expect to spend between $200 and $350 for parts and around $150 for labor.
Troubleshooting the Cause
When determining what is causing the ESP BAS light, the recommended and easiest way is to read the trouble codes stored in your vehicle’s error memory with an OBD2 scanner.
As discussed above, it’s not a good idea to guess and blindly start replacing parts. By reading the trouble codes, you can locate the issue fast and effectively, so you will get back on the road in no time!
If you don’t have an OBD2 reader, you can get one for an affordable price. And if you usually DIY car repairs, An OBD2 reader is a good investment which means you don’t always have to rely on a car mechanic to perform a diagnosis or turn off a malfunctioning light on your dashboard.
However, if you can’t get your hands on a scan tool or someone else to diagnose it, I would recommend starting troubleshooting by re-calibrating the steering angle sensor.
If the ESP BAS light does not turn off after performing the steering angle calibration, either the calibration wasn’t properly done, or there’s a big chance you have a problem with any of your wheel speed sensors.
How to Reset ESP BAS light
Ignoring the cause and resetting the ESP BAS Light does not prevent the problem. Instead, it can lead to expensive repairs and even accidents. Therefore, you should never reset the warning light before identifying and fixing the problem.
Note: If the vehicle was made before 1996, you’d need to get an original OBD code scanner. However, the OBD2 scanner will work on most vehicles made after 1996.
Follow these steps to reset the ESP BAS light with an OBD2 scanner.
- Locate the diagnostic link connector (DLC) port for your OBD2 scanner. It’s usually located under and to the left of your steering wheel.
- Connect the OBD2 code reader to the DLC port.
- Enter the requested information and select “systems” or “control unit.”
- Find ESP BAS and select “erase codes” or “reset codes.”
It should now clear the warning lights. If the ESP BAS light keeps coming back, the problem isn’t fixed.
Now that you know a little more about the ESP BAS Light, it’s up to you to do the necessary work to keep you and your vehicle safe on the roads.
The ESP BAS light is a safety feature in your vehicle that is there to protect you. And while your vehicle seems fine, you should not ignore the ESP BAS light when it comes on.
By troubleshooting and finding the cause with an OBD2 reader, you can avoid expensive repairs and, most importantly, accidents.
Thanks for reading!