By regulation, all new passenger cars marketed in Europe since the end of 2014 are required to equip the Stability control. Commonly called ESP (Electronic Stability Programme), this system can appear with many different acronyms depending on the manufacturer or brand of the vehicle. Most call it ESP but, for example, BMW calls it DSC (Dynamic Stability Control) and Alfa Romeo as VDC (Vehicle Dynamic Control).
After all, it is an unimportant curiosity, since the objective and its operation are identical. It is estimated, according to some studies, that the Stability Control can prevent about 80% of skidding accidents. It is a very high percentage that translates into many lives that reach their destination safe and sound thanks to this great invention. With this information we should forget about pressing that button that says "ESP Off" or similar, and make sure that it works perfectly.
What is ESP and what is it for?
ESP is a active security system which largely prevents loss of control of the vehicle. Developed by Bosch in the early 90s and fitted for the first time in the Mercedes S-Class in 1995, through a multitude of sensors it is able to detect if the vehicle is losing grip relative to the pavement. Most of its elements are shared with other assistance systems, such as traction control, ABS, or Hill Assist (hill start aid).
In case of detecting a loss of path acts on the brake system to reposition the vehicle and recover its grip, applying the necessary braking force on the brake disc of the wheel that needs it. It is also capable of "cutting" the delivery of power that reaches the drive wheels if at that moment we keep the accelerator depressed and if the situation so requires.
To better understand the general operation of the system, we have already prepared an extensive article on What is it the ESP. In this we will focus on the possible breakdowns, solutions and repairs without taking the car to the workshop. Unlike other faults (like the dual mass flywheel), with this breakdown it is difficult to stay stranded, but the safety of the car is considerably reduced...
Possible breakdowns in the ESP and how to solve them
Pedal or steering angle sensors
Important is also step on the brake pedal and turn the steering wheel, since it may have been a momentary fault in the brake pedal sensor or in the steering wheel rotation angle sensor.
We can try (if we are minimally crafty) to unplug and carefully clean the brake pedal sensor. As we have previously mentioned, the stability control needs to know if the brake pedal is activated or if it is not, so one of the causes of the warning light coming on could be this.
For its cleaning, there are products commonly known as “contact cleaners”, which will be applied to the connection. Take a look at the article My brake lights don't come on. In it we detail how to access the brake pedal sensor and how to manipulate it.
wheel sensors
On the other hand, it could be the case that you entered dirt on any of the sensors of the wheels or any element that prevents any of these from taking readings of the rotation of the wheels. This case is common when we have previously traveled through field or mud, as it may have remained dust, a branch or piece of mud making it difficult to see the sensor. If these circumstances have occurred, it is important to wash the vehicle paying special attention to the area of the wheel arches, wheels and brakes.
Specific failure of the ESP recorded in the control unit
If it persists, depending on the car model and/or type of fault detected by the control unit, it could have been a instant fail that has been memorized. In this case, the repair will be economical, since it would simply be a question of connecting a diagnosis machine and delete it.
ESP warning light for battery or alternator problems
We must also bear in mind that this system is powered by electrical current. That is, if the battery is about to "die" or is not receiving power from the alternator, on some models it is possible that the ESP warning light (and others) will light up. Therefore, it would not be a fault of the ESP, but rather it comes from the vehicle charging system. In the following video you can see how to check the battery and the alternator easily.
On the other hand, if we do not find the fault, in the workshop and thanks to the diagnosis machine They will locate the fault quickly. Depending on whether it was a specific fault or if it is a more serious fault (control unit, wheel speed sensor, accelerometers, etc.). The repair can be from a few euros to a few hundred euros.
What to do if the ESP warning light comes on
When the Stability Control detects an anomaly, as we have already mentioned, it stops working. To let us know about this problem, a witness with the usual command prompt (car leaving skid marks) will illuminate on the instrument panel; one of all who light up to do the “check-control” when we give contact.
First of all, if this warning light stays on when doing the initial check, we must remove the contact and turn it on again. If the warning light stays on, we will try to move the car a few meters, turn it off and start it again. We will carry out this operation because it is possible that during the check one of the sensors has not taken the reference of rotation of the wheel and after moving it a few meters it has already recovered the references.
Can you drive with the Stability Control warning light on?
A fault in this system does not prevent starting or driving with the vehicle, but we must bear in mind that in the event of a loss of stability, it will not act. This translates to the active safety of our car will be reduced considerably.
On certain models it is likely that the dynamic capabilities of the engine will be altered. Upon detecting a failure in this important security system, engine management can limit power or the maximum speed of rotation of the propeller, limiting the capacity of response, acceleration and/or maximum speed.
Elements that make up the ESP
Like any other system, there is a possibility that it will break down or works incorrectly, even if the electronics detect any anomaly in its elements, connections or operation will stop working. It is a drastic solution, but quite logical, since an incorrect operation could end up with worse results than if it did not come into action or even activate when it is not necessary, causing a loss of control of the vehicle.
The Electronic Stability Control system is composed of several electrical sensors as well as a control unit, in addition to the actuators themselves which are the brakes (ABS pump and solenoid valves). The main sensors are the following:
- steering wheel position sensor, which detects where the driver wants to steer the vehicle,
- brake pedal sensor and throttle position sensor, which detect what the driver wants to do
- yaw angle sensor (longitudinal and transverse G-force meter) and
- wheel spin sensors.
This element can catch a lot of dirt... and cause failure
With all of them, the system is capable of know what to do and if it exists drift angle. That is, if the car is turning less than it should (understeer) or more than it should (oversteer).
In most vehicles that have ESP, there is a key or mode for system shutdown. It is not advisable to turn it off except in very specific conditions such as starting off on a slope on slippery terrain and, in certain models, when a speed is exceeded or a certain period of time has elapsed, it is automatically activated again.
In short, what were you doing when the failure occurred?
Here we leave you a summary of what we have told you and in which you can see the possible breakdowns in the ESP depending on what you were doing when the warning light came on.
- I was just driving normal and the warning light stayed on: there are many possibilities and variants, but some points to check is if the battery voltage is good (sometimes an old battery can give faults in the ESP), if the fuse is not blown and if the fuse box connections are clean and sound. The cleanliness and connections of the wheel spin sensors can also be checked.
- The witness lit right when you hit the brakes: You can check that the brake light switch is working properly. If after turning off the ignition and restarting the engine the ESP works normally, check by braking very lightly (just touching the brake pedal) if the fault repeats. If so, you may just have to change the brake pedal sensor (about €30)
- The warning light came on while driving normally and just before turning on the car began to "rattle" in a strange way for a few moments. If this is your case, it is possibly a bad issue... it is possible that the steering wheel rotation sensor (about €200) or it may be that some element of the gyroscope or the control unit is damaged (from €500 and up, depending on the elements). In this case, you can do little more than take it to the workshop. When one of these very expensive elements breaks down, the car does not always have to "rattle" or make any strange noise, but if it does, it is quite significant.
- The warning light came on as soon as the ignition was turned on when the car was started. It is usually a check-control error or some loose connection. Try moving the car a few meters and start the engine again. If it persists, check the connections, fuses and cleanliness of the wheel sensors. The fuse kit for situations like these They are very cheap and do not bother under the boot floor.
If you have checked all the above points and your ESP keeps crashing, you will have no choice but to take it to the workshop.