When the ESP warning light appears in the instrument cluster, this is no reason to panic, but drivers should be aware that the system is switched off. Therefore, caution is advised. But what does this yellow indicator light mean?
The first place to start is the vehicle’s owner’s manual. There, it is explained in more detail what the indicator light means. However, the causes of faults are not dealt with there.
How does ESP warning light work in the car?
There is a revolutions-per-minute gauge on each wheel, a lateral acceleration sensor measures centrifugal forces, and a steering angle sensor checks the steering angle of the front wheels. The sensors measure the forces that occur as well as the speeds, and the control unit determines whether the car’s driving situation is stable.
When critical conditions are reached, the ESP intervenes in the movement dynamics and corrects the driver. In this way, it can defuse dangerous situations to a certain extent and make driving safer.
When the ESP warning light flashes while driving, either traction control or the vehicle dynamics control (ESP) is actively intervening in the driving process. This can be when starting, while at least one wheel develops too much slip when cornering too vigorously or in driving-critical situations such as an evasive maneuver.
If, on the other hand, the skid symbol is permanently lit, the ESP is inactive. Either at the driver’s request by active deactivation (partly in different gradations, not possible in all vehicles) or due to a fault.
Regardless of the fault displayed, the brake system as such remains fully functional. Depending on the extent and nature of the fault, other systems may fail together with the ESP.
When the ESP warning lights up?
It happens quickly: A little carelessness and the right front wheel crashes ungently against the curb. This can damage not only the tire and rim but also the suspension or the axle. This can lead to the axle geometry being permanently disturbed. And to make matters worse, the steering wheel is also crooked.
In this case – provided there is no other damage – a wheel alignment would have to be carried out and, if necessary, the steering angle sensor (LWS) recalibrated.
But there are also a number of other possible causes for the ESP warning light lighting up. Modern systems use a whole armada of sensors to determine information about the driver’s wishes and driving conditions.
Components that can trigger the ESP warning light
- Steering angle sensor
- Wheel speed sensor
- Yaw rate sensor
- Lateral acceleration sensor
- ABS/ASR/ESP control unit
- Impulse ring
To be able to locate and narrow down the fault, a fault diagnosis helps. Equipped with an OBD-II diagnostic device and the appropriate software on an Internet-enabled laptop or tablet, then search for the cause can begin.
The diagnostic device is connected to the vehicle’s diagnostic interface and the computer.
Switch on the ignition and start the software.
Once the vehicle has been selected in the diagnostic program, the OBD control unit is checked for stored fault codes.
Existing errors are listed, and the error code text gives first clues on where to look for an error.
Error codes that affect the functionality of the ESP influence can be:
If, for example, the error code C0037 – Rear left wheel speed sensor was detected during the error scan, it is reasonable to assume that the error could be triggered by this sensor or by faulty wiring of the sensor.
Does the EPC light on your car? Find out what is EPC and what does the EPC light mean?
Where errors sometimes occur
If a measuring point operates incorrectly, the system can no longer function as intended, and the warning light comes on. In addition to a defect in components of the system, other causes of ESP failure are possible. The list of such possibilities is long, and only a diagnostic device can work through it.
- The cable connections of all cables that send or forward data to the ECU must have proper electrical contact. The contacts should look bright and be tight. All four wheels have their own sensor.
- Measure the on-board voltage. Some units will respond with an error message if the battery is tired or partially discharged. If the voltage exceeds eleven volts, the battery is ruled out as the cause.
- Have an assistant tell you whether the brake lights are working. A defective brake light switch cannot be ruled out as a source of error.
- Check the relevant cables for chafing or breakage. You can localize a cable break with the continuity test. Connect the cable in question to a circuit. As soon as the current is running, everything is okay. The simplest tool for the test is a test lamp for twelve volts. Worn insulation is a result of loose hanging or crushed cables.
You must go to the workshop if you cannot find and rectify the fault with these measures or if a system-relevant component is defective. The diagnostic device determines the faulty component and deletes the error from the control unit. Occasionally, change phenomena occur that only a specialist can diagnose.
For example, the light for a defective ABS lights up, although another fault is present. It is also possible that the warning light lights up for both safety devices – ABS and ESP. The car does not have to stop immediately because of this.
ESP warning light – From problem to solution
If the ABS sensor provides no or implausible readings, the ESP/ASR/ABS control unit cannot detect if there is too much wheel slip when starting on a rear-wheel drive vehicle. The traction control system does not detect a wheel that is spinning, and the system deactivates itself to prevent incorrect control interventions.
You can gather enough initial information on the Internet, and advice can be obtained from the online auto repair shop to help solve the problem. Then it is necessary to determine whether the cable or the component causes the fault.
Since testing a wheel speed sensor may only be done with an oscilloscope, only experienced and professionals should check the sensor. For example, a resistance measurement is not possible, and this would destroy the sensitive sensor.
Removal and installation of the speed sensor, on the other hand, is not very complicated.
Get on the lifting platform, remove the wheel, and loosen the plug connection and screw, pull off the sensor. Before installing the new sensor, inspect the impulse ring, and clean everything thoroughly. It is important to pay attention to the correct tightening torque.
Continue driving if it lights up?
Don’t panic if the light indicates a fault. A car drives home without ESP just as it does with ESP. Behave in traffic in such a way that no dangerous situations arise. If you drive permanently with a defective system and an accident occurs, there are serious consequences.
You may lose your insurance coverage because the provider accuses you of negligence. A defective ESP is considered a serious defect at the general inspection. You will not receive a sticker as long as the fault indicator is lit.
If your car has the electronic stability program installed, it would be irresponsible not to use it. You are still responsible even if there are annoying disputes with the workshop or the manufacturer. Some drivers experience such conflicts when damage has to be settled.
If you are planning to buy a car, you would be well advised to find out about the experiences of other owners of the same type. There are helpful forums on the Internet and in the trade press.
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