Wheel Alignment - Advanced Driver Assistance Systems (ADAS)

North, South, East & West: Finding The Right Direction In Modern Wheel Alignment Technology

For the past 100 years, wheel alignment has been about adjusting camber, caster and toe angles. During the past 20 years, four-wheel alignments have done their share to change the wheel alignment landscape. But, with the introduction of the 2018 and 2019 imports, Advanced Driver Assistance Systems (ADAS) are once again revolutionizing the wheel alignment market because the alignment technician must not only align all four wheels with the vehicle centerline, he must now align one or more ADAS sensors with the lane of travel.

For the past 100 years, wheel alignment has been about adjusting camber, caster and toe angles. During the past 20 years, four-wheel alignments have done their share to change the wheel alignment landscape. But, with the introduction of the 2018 and 2019 imports, Advanced Driver Assistance Systems (ADAS) are once again revolutionizing the wheel alignment market because the alignment technician must not only align all four wheels with the vehicle centerline, he must now align one or more ADAS sensors with the lane of travel. In other words, “getting it right” in wheel alignment means that the wheels and all respective sensors must be traveling in exactly the same direction. As we’ll see in the text below, ADAS will not only change how we do alignments, it will change some of our management and pricing practices as well (see Photo 1).

Photo 1: Subaru’s ADAS “Eyesight” technology for this 2019 Outback includes adaptive cruise control, acceleration cut-off, distance control, lane-keeping, blind-spot assist and back-up camera.

To begin, we have a lack of standard ADAS terminology among auto manufacturers, so I’ll try to use self-descriptive words. And, while ADAS includes many driver conveniences, our focus will be on the safety aspects of ADAS as it pertains to wheel alignment.

ADAS sensors generally consist of one or more cameras mounted inside windshields, ultrasonic transmitters mounted flush on fenders, back-up cameras at the rear bumper, and radar units mounted in the front grille area or rear sheet metal and bumpers.

As of this writing, I’ve counted 31 ADAS features that are sold as standard and optional equipment. These ADAS features include adaptive cruise control/active braking, blind-spot monitors, lane departure warning, lane change assistance, driver drowsiness detection and crosswind stabilization systems, to name but a few. Standardized ADAS features also include conventional tire pressure monitoring systems (TPMS), anti-lock braking systems (ABS), electronic stability controls (ESC) and electronic power steering.

Photo 2: Global positioning system (GPS) data is a vital input for any ADAS-equipped, semi-autonomous driving feature.

New ADAS-equipped vehicles might also have the ability to drive themselves along specified routes (see Photo 2). Needless to say, global positioning systems (GPS) are essential for identifying the immediate location of the vehicle. Current semi-autonomous vehicles include cameras that can read the yellow lines bordering most major highways and turn lanes. Fully autonomous vehicles would include traffic navigation systems, more sophisticated collision avoidance and lane change assistance systems.

A number of conventional safety systems supply ADAS with vital inputs. Before the advent of ABS, the driver would manually “pump” the brake pedal to maintain directional steering when braking on slick road surfaces. ABS now automatically “pumps” the brake pedal by modulating hydraulic braking pressure in response to wheel speed sensor inputs.

Electronic stability control (ESC) is the logical outgrowth of ABS because ESC uses the ABS hardware to steer the vehicle via the service brakes during an emergency situation. In brief, an ESC accelerometer located in the vehicle measures “G” force inputs that are compared with a normal range of G-force profiles stored within the ESC module. When G-forces indicate a driver control problem, the ESC module then pulses one or more brakes to help steer the vehicle out of a potentially catastrophic skid.

With the advent of electronic throttle controls (ETC), the driver supplies an electronic input through the throttle pedal. That input is translated by the PCM or dedicated ETC module into a specific throttle opening by a pulse-modulated electro-mechanical motor. Since throttle position is relayed to the PCM and other modules, electronic throttles have replaced conventional cruise controls and traction controls. Electronic throttle control data is also shared by the safety-related ADAS systems located throughout the vehicle. To illustrate, ADAS will automatically slow the vehicle by closing the throttle when it detects a potential obstruction in the driving lane.

Active braking systems (also called active cruise control) use a small, forward-looking radar unit to measure closing speeds against objects located in the driving lane. At predetermined distances and closing speeds, the active braking module automatically activates the service brakes to avoid or reduce the effects of a head-on collision.

Last, but not least, electronic steering systems have become the focal point of ADAS because a steering torque and a steering wheel position sensor contained within the assist unit shares their data with ADAS systems. ADAS not only senses steering torque and direction, but it can command the steering wheel to steer the front wheels in conjunction with an ADAS parking assist feature.

While automatic steering wheel activation is currently used in assisted parking, it could be used in some configurations for accident avoidance. In addition, steering effort and ratio can be customized to the driver’s tastes, not to mention that electronic steering can “buzz” the steering wheel to alert a sleepy driver when he or she is drifting out of their driving lane.

While some ADAS systems process information from a single sensor, most ADAS systems share information from many different sensors. Since ADAS configurations are nearly infinite, suffice it to say that a deficiency in one system might affect the performance of another.

In many cases, ADAS component systems aren’t affected by routine wheel alignments. But ADAS components, like the cameras mounted inside a vehicle’s windshield, must be realigned if the windshield is replaced. Other ADAS components must also be realigned if the vehicle has suffered minor sheet metal damage, major structural damage or undergone a major mechanical repair that might alter ADAS sensor alignment in relation to the vehicle’s driving lane.

If an ADAS sensor is misaligned, a DTC should, in theory, be stored and an instrument panel warning light should illuminate. But that isn’t always the case with some radar sensors because ADAS evidently has no way of rationalizing an alignment failure.

To date, dealerships and collision repair shops are doing most of the ADAS-related repair work. That said, ADAS will most certainly work its way into the service bays of shops equipped with alignment machines. While auto manufacturers currently supply most of the special tooling, I would suspect that improved tooling will make its way into aftermarket shops. As they have in the past, many alignment machine manufacturers might integrate ADAS calibration software and service information into their own hardware and software systems. And, many alignment companies might also supply the required tooling under their own brand names.

As of this writing, most independent shops aren’t servicing enough 2018 and 2019 vehicles to get a firm grasp of the tooling and training needed to service ADAS technology. But, as ADAS vehicles accumulate miles, service will be needed.

In any case, ADAS-related tooling and training will be required to perform ADAS-related calibrations and repairs, and that cost must be factored into a shop’s hourly rate. Depending upon its individual experiences, a shop might find it more cost-effective to focus upon its most popular vehicle platforms when performing ADAS-related wheel alignments. At this point, I would invest in training and tooling based upon recent experience rather than upon blue-sky speculation.

In response to ADAS technology, menu-priced or promotionally priced wheel alignments should become a thing of the past. Pricing might instead become application-specific, depending largely upon the number of ADAS-related services required to align a specific vehicle. Depending upon individual returns on investments (ROI), tooling costs might also increase hourly rates. In short, the days of “toe and go” alignments are on the wane. Instead, occupant safety, through the auspices of ADAS, will become a primary focus of the undercar service industry. And it well should because nothing can replace a human life.


Adapting to ADAS: A Service Overview

1. Your enhanced aftermarket or OEM scan tool is your best friend when diagnosing and adjusting ADAS components.

2. Avoid symptom diagnostics by using a data-based diagnostic approach.

3. ADAS diagnostics requires a systems approach. Avoid “tunnel vision” by diagnosing the whole vehicle instead of its individual parts.

4. Calibration includes static and dynamic methods. Depending upon application, both might be required to accurately calibrate windshield cameras and other sensors.

5. Forward-looking radar sensors used in active braking must be perfectly level so the beam won’t project above or below the vehicle ahead.

6. Since a lateral deviation of one degree might well invalidate any forward-looking ADAS radar sensor input, the chassis centerline (or thrust line) must align perfectly with the lane of travel.

7. ADAS is CAN-based, so you’ll need to understand CAN diagnostics.

8. CAN diagnostics will vary according to application, so learn theory and practice first, applications second.

9. Some ADAS systems require paper targets that must be placed 10 to 20 feet in front of the vehicle. This procedure usually requires extra-deep and perfectly level service bays.

10. As with any alignment, ADAS calibrations normally require that the vehicle be unloaded and that the ride height is within specifications. Tires must be properly inflated, fuel tank full, and the windshield clean in front of each camera sensor.

11. ADAS adjustments usually require a four-wheel alignment beforehand or an alignment check prior to servicing.

12. ADAS is safety-related and, therefore, involves potential liabilities, so use manufacturer’s service information and special tooling as a matter of practice.

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