Receiving a service stabilitrak/brake system/ traction control simultaneously….started about 2 weeks ago.

ANSWER : Hello. The stability control and traction control warning lights can trigger for several reasons. The first step you will want to take will be to have the vehicle scanned for diagnostic troubleshooting codes. This will tell you what about the systems is malfunctioning. The ABS system works hand in hand with the traction control and it may have more to do with the ABS system then the traction control. Due to the lights flashing on and off, you may simply have a loose connection or wire. The service tire monitor is realistically the most important warning. If the tire monitoring system is failing on one or more tires, the traction control and stability control systems will not have the input from that sensor to make calculations. Start by having the vehicle scanned, and use that information to help the diagnosis.

ANSWER : Hello. These systems are interconnected, since both of them can control individual wheel brake functions when operating. It is likely that one of the speed sensors are failing. To have this verified, have a qualified professional, like one from YourMechanic, diagnose the warning lights, pinpoint the fault(s), and make necessary repairs.

ANSWER : Hi there, thanks for writing in.

It sounds like you are having a serious electrical malfunction, which is very hard to diagnose without being able to look at the car first hand. The first step to diagnosing your electrical issue would be to scan all the relevant control modules in the vehicle, to see if there are any faults relating to any of these issues. It sounds like somebody at the dealer has been trying to fix this problem, so it may be a more involved one. I have personally seen failed control modules cause things like this, but that is no guarantee that it’s the problem in your case. It would be best to have a qualified independent technician, such as one from YourMechanic, look at your car to diagnose your electrical problem.

ANSWER : Hello There,

It sounds like your problem could easily be related to either of the two scenarios you have proposed because in all likelihood, either of these situations could produce the symptoms you are describing. One of the most common causes of the brake pedal going to the floor is a loss of brake fluid. Generally, this is easy to detect due to the fact that there is usually brake fluid leaking on the ground underneath the vehicle. The brake booster is a mechanism that uses vacuum pressure to take the force being applied to the brake pedal and amplify it. If the booster is bad, then the full amount of force needed to activate the master cylinder and pressurize the brake fluid isn’t going to be there. This is where the spongy brake pedal comes in.

Another possible cause for this may be a failing master cylinder. The master cylinder is where the brake fluid is compressed creating the necessary hydraulic pressure the braking system needs in order for it to stop your vehicle. When the master cylinder fails, this may cause a loss of hydraulic pressure which will usually also cause the brake pedal to go to the floor. I would recommend having an expert from YourMechanic come to your location to diagnose your braking system.

ANSWER : The brake pedal is working to stop the vehicle, but there may be air in the controller unit causing the ABS brakes to not function. I recommend bleeding the brake system from the farthest location from the master cylinder to the master cylinder including the ABS unit. If the brakes are still spongy after a full bleed, then the controller will need to be replaced. If you need further assistance with your brake pedal being spongy, then seek out a professional, such as one from Your Mechanic, to help you.

ANSWER : ABS, traction and stability control systems rely on input from a number of sensors to function properly. Faults can be in any one of them from the brake light switch, steering angle sensor, wheel speed sensor, or up to a dozen others. Also, a fault code can be present for any of the sensors without the sensor itself being the actual fault. A wiring issue to that sensor or a fault in the abs/traction control computers can also be the cause. The only sure way to find out why the abs and traction control lights are on is to diagnose the system properly. The airbag light can be related if for example, the steering angle sensor is faulty as it provides input for the airbag system as well as abs, traction, and stability control systems. It can also be a stand-alone issue. When the system is scanned, fault codes will provide a direction to take in diagnosing the problem, but isn’t always as simple as replacing "Sensor A". Replacing parts without confirming they are actually the cause of the fault can be more expensive in the long run. Most electronic parts are not returnable once installed so if you replace a random part that does not correct the problem, you are stuck with the cost of that part and still have the same issue.

ANSWER : Hi there:

You would be correct to assume that these warning lights are related. In fact, in most cases, if the right sensor is bad or the electrical connection to the sensor is faulty, it can trigger all three lights. To know for certain which sensor or mechanical component is sending the warning to the ECU, you’ll need to have a professional mechanic complete a check engine light is on inspection, so they can download all error codes stored in the ECU and determine which is faulty; so they can recommend the right repairs.

ANSWER : It’s possible to have someone alter the brake pedal or adapt a brake pedal from a different vehicle. You may call around to some customization shops to see if anyone is interested in taking on the project. But first, I would try reaching out to the selling dealer with your concern – especially since it is a new model. Good luck.