What Does the ESP BAS Light Mean & How Do You Fix It?

In this article we will be looking at the ESP BAS warning light to demystify it. We will find out what it means, what might cause it and how you should deal with the situation. Warning lights need not be scary if you understand their meaning and take action quickly.

What Does the ESP BAS Light Mean?

The ESP BAS warning light actually is an indication of an issue in either of two systems. Your issue may relate to the Electronic Stability Program or the Brake Assist Program. This unfortunately means that it could indicate several potential issues.

You will get this light when either of these systems develops a fault. The severity of the issue can range from minor to major. In order to know exactly what the problem is you should either seek the help of a mechanic or make use of an OBD2 scanner tool.

What Can Cause the ESP BAS Light?

As mentioned there are many potential causes for the ESP BAS warning light. A great way to get the bottom of the issue quickly is to use a scanner tool. These tools allow you to connect to the car's computer and read the trouble codes.

Using the trouble codes you can then check a list of codes for your specific model to determine where the problem actually is. This is a great way to determine whether the problem is something you can fix yourself or if you may need to visit your mechanic.

If you do not have a scanner tool then here are a few possible causes of the ESP BAS warning light:

Defective Steering Angle Sensor

The ESP aspect of the warning light refers to your car's version of a stability program which means it can make adjustments to your car in the event that you encounter slippery road conditions. It works in conjunction with anti-locking brakes (ABS) and traction control.

Essentially if the sensors in your wheels detect that one or more of them may be losing traction the car's computer adjusts the power and braking to the affected wheels. The wheel sensors are not the only ones involved however as the steering wheel angle sensor is also part of the process.

The steering angle sensor tells the computer what direction the wheels are pointing which is also used to calculate what action to take when your tires start to slip. If this sensor does not send the correct information then the ESP system can not make the needed calculations so therefore can not work.

This is one of the most common sources for this error.

Bad Wheel Speed Sensor

We have already mentioned the wheel sensors as being important to the ESP system. Each wheel will have one of these sensors and it tracks the speed at which the wheels are rotating. When we hit a patch of ice and the wheel starts to slide the speed changes and this is logged with the sensor.

The warning of a sliding wheel gets sent to the car's computer where combined with other data a calculation for brake force or power adjustment is made. This is quickly enacted to help prevent the driver from losing control of their vehicle. To say ESP saves lives would be an understatement.

It should be noted that the ESP BAS light will come on briefly while the system makes adjustments to counteract the road conditions. This is just a warning that the system is currently making changes. You should actually feel braking occur on a specific wheel to help correct the car so do not worry about the light in this case as it should turn back off.

Failed Brake Switch

Also known as the brake light switch this small part is located in your brake pedal. When you press your brakes it activates the brake lights and it also sends important data to the computer which will relate to the ESP BAS systems operations.

If this switch breaks not only does it affect your brake lights but it can also mean the ESP BAS system can’t do its job. Based on your brake lights alone not working you will want to fix this issue without delay and thankfully this is easy to diagnose. In fact many times at a regular oil change the technicians may have you test your rear lighting and can tell you if your brake lights do not come on.

Brake Problems

Issues with your brakes can often be the cause of the ESP BAS warning light. Over time brakes wear out and parts need to be replaced. If you already know your brakes are starting to struggle because they are becoming noisy or less responsive you may want to get these dealt with.

You may find that after having pads, rotors or calipers replaced that the ESP BAS issue has been resolved.

Wiring Issues

The ESP BAS system relies heavily on electrical components which all need to be connected somehow. This is done with extensive wiring and if you know anything about cars and electrics you know that wiring takes a beating over time.

The wires anywhere in the system may develop damage, corrosion or simply just become loose at the connections. This can be tricky to diagnose and is a little rarer in modern cars thanks to extra protection but it certainly is not impossible.

Can You Drive With the ESP BAS Light On?

This is a question that gets asked about so many automotive issues and with the financial worries of our time it is understandable. People want to know if they can keep driving for a while until they can afford to make the requisite repairs.

Technically the ESP BAS system is an additional driver aid that older cars never had so if it doesn’t work you would be on your own to deal with bad road conditions. You may be fine with that and feel confident in your skills.

The problem is that depending on the issue it may be far more unsafe to drive with the ESP BAS system faulty than if you just didn’t have such a system. The brake light switch issue for example needs to be fixed not only for safety but because legally you must have an operational brake light.

You must also remember that the system's job is to apply brakes when it assesses a threat of sliding on the road surface. If sensors are sending incorrect information this may lead to the system applying brakes when no such adjustment is needed. The result of this could be a nasty crash.

The answer then is although the car should run fine otherwise you should not ignore an ESP BAS warning light. The issue may be minor right now but it can get worse and potentially cause an accident.

Fixes for the ESP BAS Light

Some of the issues we have discussed can be fixed with ease if you know what you are doing or if you do not feel confident you can seek the assistance of a mechanic. For those who like to work on their own cars read on for some tips.

Check the Trouble Codes

We mentioned earlier about the OBD2 scanner tool and we can not stress enough how valuable one of these can be in your home garage arsenal. They can help you quickly get to the bottom of what ails your car and help you plan your next steps.

In some cases you may even be able to fix your issue using this scanner tool so look out for that as you read on further.

Recalibrate or Replace the Steering Angle Sensor

The issue with your steering angle sensor may be that it needs replacing or it could simply have become poorly calibrated. It is not a particularly hard process to recalibrate this sensor and it can often be done without the need for special tools.

You can also potentially use your OBD2 scanner tool to perform the recalibration. Check your car's manual for tips on recalibrating the sensor in your specific model or you can often find instructions online.

Replace Wheel Speed Sensors

If there is an issue with a specific wheel speed sensor it is in all likelihood broken and will need to be replaced. This is a pretty simple fix although you will likely have to take the wheel off to be able to easily access the sensor.

Once the wheel is off and as long as the sensor isn’t rusted you should be able to just pop out the old unit and replace with a new one. Again check the process for your specific vehicle as this can vary and we should never assume that it will always be the same.

Replace the Brake Switch Sensor

This one is also pretty simple to do. You should start by locating where in your brake pedal the switch will be found. This again may be a job for your owner's manual. Once located it should be a case of removing the old switch and replacing it with a new functioning one.

You will likely need to reset your ESP BAS warning light afterwards though but this can be done using your OBD2 scanner tool.

Replace Brake Parts

Brakes are important to the operation of the ESP BAS system so they need to be in good working order. You often do not have to replace all of the aspects of your brakes at once but particular parts may be worn out and need replacement.

This is a trickier fix and does take a certain level of skill. Remember these things are what stop your car so if you do a poor job of replacement it may not only endanger you but other road users. If you feel confident to do this project however make sure to find instructions specific to your make and model of car.


The ESP BAS system has saved countless lives and will continue to do so as long as you make sure to deal with any issues that arise with it in your own cars. There can be a number of causes for receiving this warning light so the first step is always going to be diagnosing the issue.

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