Any Illuminated warning light is a cause for concern.
The check engine, oil pressure warning, brake system, and temperature warning lights are some of the indicators that car owners don’t want to see flashing in front of them while driving.
The same goes for the service electronic stability control (ESC) light, which is triggered by certain conditions.
What Does an Illuminated Service ESC Light Mean?
An illuminated service ESC light can mean a couple of things.
The first one is that there could be a system malfunction. Under this circumstance, the service ESC light will stay on until the issue is resolved.
The second one is that the ESC system is trying to restore vehicle stability, causing the ESC light to flash. This usually happens whenever you’re driving on slippery roads.
What Causes the Service ESC Warning to Light Up?
Two conditions can cause the ESC warning lamp to flash一oversteering and understeering.
Oversteering occurs whenever the rear of the vehicle breaks loose. Depending on the direction, the ESC system will activate either the right or left front brakes to restore stability.
For example, if the vehicle spins out of control while making a left turn, the ESC system will engage the right front brakes.
The service ESC light will also illuminate once the system detects understeering. This means that the front of the vehicle moves in a straight line even when the driver is trying to make a turn.
Depending on the direction of the turn, the ESC system will activate either the right or left rear brakes to restore vehicle control.
What Causes the ESC System to Malfunction?
A malfunctioning ESC system won’t necessarily affect your vehicle’s drivability, but you’ll be left without a backup in case of emergencies. Below are the most common reasons why the ESC system can fail.
ABS Issues
The ESC system relies on the ABS to work effectively. Issues like worn brake linings and contaminated brake fluid can restrict ESC operation.
Faulty Sensors
Damaged or faulty sensors won’t be able to relay vehicle movement information to the ESC system, which can limit its functions.
Wiring Problems
The ESC system gathers information from various interconnected sensors. Damaged or corroded wiring can prevent the system from communicating with other components, affecting its overall operation.
Software Malfunction
Similar to other electrical systems, software issues like bugs and glitches can also cause the ESC system to malfunction.
The Need for an ESC System
According to the Federal Motor Vehicle Safety Standard (FMVSS) no. 126, all passenger cars, multipurpose passenger vehicles, trucks, and buses with a gross vehicle rating of 10,000 lbs. or less should have an ESC system. This applies to all vehicles manufactured from 2012 onwards.
ESC System Requirements
The ESC system should be able to perform the following functions:
- Activate all four brakes individually in vehicles with a four-channel anti-lock braking system
- Work during acceleration, coasting, and deceleration
- Work simultaneously with the ABS or traction control system (TCS)
ESC Switch
Some vehicles have an ESC switch that lets drivers temporarily deactivate or limit the system’s functions during certain conditions.
These include traversing across sand or gravel and operating a vehicle while on a racetrack.
Vehicles with an ESC switch can reactivate the system when the ignition is turned on.
A Closer Look at the ESC System
The vehicle stability system is designed to mitigate loss of vehicle control by measuring yaw (sideways movement) and acceleration along with wheel speed, steering angle, and torque along with other inputs. The ABS unit can autonomously apply the brake on just one wheel of its choice to correct an oversteer or understeer situation. The system may be referred to as Advancetrac, Electronic Stability Control, Stabilitrak, etc., depending on the manufacturer.
Several sensors help the ESC system identify whether it needs to activate one of the brakes to restore vehicle control. Let’s take a look at some of them.
Steering Wheel Position Sensor
The ESC system relies on the steering wheel position sensor to determine the driver’s intended direction. It can also be referred to as the hand-wheel position sensor.
Vehicle Speed Sensor
The vehicle speed sensor is a magnetic sensor that generates an analog signal that’s directly proportional to speed.
The electronic brake control module (EBCM) also uses this sensor to help control the suspension system.
Lateral Acceleration Sensor
The lateral acceleration sensor provides vehicle cornering information to the suspension control module.
By sending the right signals, the suspension control module can provide the appropriate damping on the inboard and outboard dampers during cornering.
Yaw Rate Sensor
The yaw rate sensor monitors how far the vehicle has deviated from the driver’s intended direction. It sends the information to the suspension control module and EBCM.
ESC and Traction Control
Traction control (TC) can come as a separate feature or one that’s included in the ESC system.
This feature lets the ABS control wheel spin during acceleration and uses the same wheel speed sensors as the ABS.
In most modern vehicles, a “TRAC CNTL” indicator light or “TRAC CONTROL ACTIVE” message pops up on the dashboard to alert the driver that the wheels are losing traction.
Similar to the ESC system, traction control also engages the brakes individually to prevent the wheel from slipping during acceleration.
In some vehicles, drivers can disengage traction control by flipping a dash-mounted switch. Doing so will cause an indicator light to stay on unless the driver reactivates the feature.
The Bottomline: Should You Worry About an Illuminated Service ESC Light?
It depends on how the ESC light looks. A service ESC light that won’t turn off can point to a system malfunction.
Although you’ll drive fine without it, the ESC system definitely comes in handy in case of emergencies, so you might want to have it checked when the warning light pops up on your dash.
Meanwhile, a flashing ESC light means that the system is activated and working as it should, which is something you shouldn’t worry about.
In most cases, the ESC system will engage when it detects that the roads are slippery or icy. Together with the traction control feature, it can also operate when the system detects that a tire is losing traction.
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Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.
