Service ABS System, Traction Control System and Service Stability System

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 : 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 : Your vehicle is equipped with both a vehicle stability control system (VCS) and a traction control system (TRAC). They operate independent of your input – they come on and off automatically, without you having to do anything. They will automatically engage when the car’s computer detects slipping, or if a wheel spins free. You will see the VSC/TRAC light come on in the dash when they activate. You’ll also hear a buzzer.

You can disable VCS and TRAC if you need to. This can be necessary in some conditions, as both systems will divert power from the drive wheels to stop slipping. To turn them off, just push the TRC button on the dash. You’ll see a light on the dash that reads AUTO LSD come on and the TRAC Off light will also illuminate. The slip indicator light will flash.

When you push the TRAC button again, the lights should go out and the VSC and TRAC systems should go back to automatic operation.

Tips

VSC and TRAC are enabled every time the engine cranks, even if you turned them off before shutting it down.
If you turn off the TRAC system only, it will re-enable when you pick up speed.

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 : You’re getting into an area that is kind of a dark art when you’re getting these kinds of codes. While I don’t know any of the symptoms that the car is exhibiting, I can tell you that failure in one of the control units can lead to codes showing up in the others and the ABS, ESP is a likely culprit since it interprets the wheel speed signals and sends the information to the other modules. You’re right that the module has to be coded, and I don’t think that Snap On has the software for that so the only place to go is the Star Diagnostic. (The consumer version of the Mercedes SDS ) You can Contact YourMechanic and see if anyone in your area has the appropriate equipment for this. Otherwise, this may be a case that would best be consigned to the Mercedes Dealer.

ANSWER : The Powertrain Control Module needs to be scanned to see if there are any stored codes. A possible issue could be the mass air sensor, as this sets up initial injection timing. The air mass meter needs to be removed to be inspected and possibly cleaned. You should also check the induction system connections, such as hose clamps and induction system piping, for cracks or looseness.

Other possibilities include contaminated connections at the Powertrain Module, but generally this will illuminate the Check Engine Light whereas a faulty air mass meter will not. You may want to enlist the help of a mechanic, such as one from YourMechanic, who will be able to read out and correct codes for your Traction Control Light and correct the engine’s loss of power issue.

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 : Hi there. Take a digital volt meter and check the voltage on the harness to the ABS control motor. There should be a battery voltage present. If the voltage is low, then there is a break in the wiring from the computer to the ABS control motor. If the voltage is normal, then the ABS control motor has a burned cell and the ABS controller assembly would need replaced. This will effect the ESP system as well and set off the lights. If you need further assistance with your ABS system not working, then seek out a professional, such as one from Your Mechanic, to help you.