Technology drives innovation, especially in the automotive industry. In the past, when a driver was faced with the instant decision to make an aggressive move to avoid an accident, they had to rely on talent and a little bit of luck to keep the vehicle under control. In recent years, automotive manufacturers working with automotive safety experts like SEMA and SFI have developed advanced stability control systems that help a driver maintain control of the vehicle during evasive maneuver situations. One of the most popular types of units on today's vehicle is known as the steering angle sensor.
The steering angle sensor is a component that makes up the electronic stability program (ESP). Each manufacturer has their own proprietary name for this advanced safety system, with some of the popular ones being: AdvanceTrac w/Roll Stability Control (RSC), Dynamic Stability and Traction Control (DSTC), and Vehicle Stability Control (VSC). Although the names are unique, their primary function and the individual components that comprise the system are virtually identical. The steering angle sensor is one of the monitoring devices located near the front suspension or within the steering column. In years past, this device was analog in nature, measuring the voltage changes that were created by the steering wheel and relaying that information to the vehicle's ECU. Today's steering angle sensors are digital and are comprised of an LED light that measures the angle of the steering input.
This component is one that is designed to last the lifespan of the vehicle. However, like any other sensor, the steering angle sensor can wear out or fail completely due to multiple factors beyond the control of most vehicle owners. When it does break or is slowly beginning to fail, it will exhibit a few common warning signs or symptoms. Noted below are a few of the common symptoms of a damaged, bad or failing steering angle sensor.
1. Traction Control Light comes on
In most cases where an issue exists with the electronic stability program, an error code is triggered and stored inside the vehicle's ECM. This will also trigger the Traction Control Light to illuminate on the dashboard or instrument control panel. When the traction control is engaged, this light does not come on, as it's typically a default position that must be manually turned off by the driver. When the steering wheel angle sensor fails, there is a malfunction indicator on the instrument cluster that alerts the driver that the electronic stability system has been disabled and requires service. In most cases, this warning light will be the Traction Control Light on most domestic and import cars, trucks and SUV's.
When the Traction Control Light is illuminated while the system is active, it's important that you contact a local ASE certified mechanic so they can download the OBD-II error codes and determine what problem exists that may impact the drivability and safety of your vehicle.
2. Steering wheel is loose and has "play"
Since the steering angle sensor is designed to monitor the actions and input provided by the steering wheel, it sometimes can relay false information to the ECM and create a potentially dangerous situation. When the sensor is faulty, misaligned, or damaged, the information it reads and sends to the vehicle's on board computer is inaccurate. This can cause the ESP to provide steering input or adjustments at the wrong time.
In most cases, this will lead to a "loose" condition in the steering wheel, where the amount of steering input you provide is not reciprocated by the action of the vehicle. If you notice that the steering wheel is loose, or that the steering is not responding the way it should, contact a mechanic so they can inspect the ESP system and fix the problem quickly.
3. Car drives differently after a front end alignment
Today's steering angle sensors are attached to multiple points within the steering system. Since a front end alignment is designed to align the front wheels along with the steering wheel, it can cause problems with the steering angle sensor. It's very common for many mechanic shops to forget to reset or realign the steering angle sensor after they've completed their service. This can cause the symptoms above to occur, such as lighting the Traction Control Light, Check Engine Light, or impacting the drivability of the vehicle.
Having complete control over your steering is essential for safe operation of any vehicle. As such, if you notice any problems as described in the information above, please contact one of our professional mobile mechanics from YourMechanic. Our team has the right experience and tools to diagnose your problem and replace the steering angle sensor if this is what is causing your issues.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Steering Angle Sensor and was authored by Timothy Charlet.