ADAS Sensors: Steering Angle Sensors and Common Calibrations

As modern vehicles come with more advanced safety features, they’re also coming with much more advantaged technology. 

Mechanics and shops are being tasked with not just fixing an engine or conducting a wheel alignment, for example, but ensuring that your ADAS sensors and cameras are calibrated correctly so features like lane keep assist will work as they should. 

Today, we’re going to talk specifically about steering angle sensors and everything mechanics need to know about how they work, which ADAS features utilize them, and how to detect signs that recalibrations may be needed. 

What is a steering angle sensor? 

Steering angle sensors (SAS) are extremely commonplace— and extremely important— in most modern vehicles. It measures the position and rotation of the steering wheel, communicates with your car’s computer system, and is critical in key ADAS features. 

The SAS monitors how far drivers turn the steering wheel and how quickly, enabling the car’s systems to react with extreme precision according to the driver’s commands. It allows the vehicle to understand and respond to your inputs, and without it, many ADAS features wouldn’t work as well. 

There are two types of steering angle sensors:

1. Analog sensors: Typically use a potentiometer setup, which has a resistive track and wiper that moves alongside the steering wheel as it turns to change resistance and output according to driver input. 
2. Digital sensors: Typically use LED technology and optical or magnetic encoding, and are thus capable of providing more reliable readings. They measure the exact angle of the steering wheel with a light source, using a photodiode to detect the movement of a coded disc that’s embedded in the steering shaft. 

Today, many vehicles leverage digital sensors, which can offer enhanced performance and facilitate ADAS safety features. 

Which ADAS features use the steering angle sensor? 

The steering angle sensor provides essential data that helps the following ADAS features operate effectively:

• Lane keeping assist (LKA): The SAS helps the LKA system determine the driver’s intended path and helps keep the vehicle within lane with subtle steering adjustments.
• Blind spot monitoring (BSM): The SAS’s data helps the BSM system interpret the driver’s steering and account for it when preventing potential collisions in their blind spots.
• Adaptive headlights: The sensor’s data can help the adaptive headlights system adjust the direction of headlines according to the steering angle to improve driver visibility as they go around curves. 
• Electronic stability control: This system assesses if a vehicle is losing control so it can take corrective actions if needed, and leverages data from the SAS. 

Many of these features rely on multiple sensors or cameras to function effectively. 

Blind spot monitoring, for example, may also get data from radar sensors to identify objects and vehicles in the driver’s blind spot. They’ll detect another vehicle with the radar sensors, and if they get data from the driver’s SAS that they may steer towards the other vehicle, it will provide a warning or prevent them from doing so. 

Signs of issues with steering angle sensors 

If your steering angle sensor isn’t properly calibrated or is malfunctioning, it can cause issues with the ADAS and electronic stability control (ECS) system. 

Customers may come to your shop reporting the following:

• An inconsistent steering response while driving, which may cause the vehicle to veer towards one side while driving.
• Steering feels different, with customers complaining that the steering feels like it has more or less resistance than normal when driving. 
• An ESC warning light, which will turn on when the system detects an error between the vehicle’s driving path compared to the driver’s steering input. This may be the first sign something is wrong.
• Issues with stability control, including loss or impacted electronic stability control, traction control, or active steering. 
• Increasing tension of the tires, which cause squeaking sounds and may result in an incorrect wheel alignment. 
• ADAS features not working correctly, including lane keep assist or adaptive cruise control. 

When you need to recalibrate steering angle sensors 

It’s important to recalibrate steering angle sensors following these circumstances: 

• Your team or a client notes any of the potential issues discussed above. 
• Conducting a four-wheel alignment. 
• Repairs following even minor collisions.
• Replacement of suspension parts. 
• Deployment of the client’s airbags. 
• Replacing components that impact toe and thrust angles, which may include tie rods, control arms, or the steering rack.

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Some makes and models may need scanners to properly diagnose which calibrations are needed during the repair process. 

Offering steering angle sensor recalibrations with Revv 

While offering ADAS calibration services can be a significant revenue driver for mechanics and shops, it’s also important to consider that it’s an essential service clients need.

We estimate that 60% of repair estimates don’t include calibrations, which is ultimately a functionality and safety concern for customers. For example, if you replace their suspension parts but fail to recalibrate the steering angle sensor, the customer’s car could veer off to the side while driving and be a hazard to themselves and drivers in the next lane. 

Revv can help you offer calibrations confidently to your clients. The REPAIR Act requires that manufacturers provide access to OEM diagnostic data and establish clear safety protocols in terms of standardized calibration procedures.

You can use Revv’s extensive library to look up any vehicle’s VIN and access its OEM data, including specific procedures to follow during recalibration processes. We’ll help you identify every billable ADAS calibration so you can maximize your revenue and help clients ensure that their vehicles are road-ready. 

Ready to offer calibration services and boost your revenue? Get your free demo today.