The biggest problem we have with ADAS systems today is neither with the sheer number of them in use on various makes and models, nor is it with the way they are integrated into each other, or even with the fact that the failure of one ADAS system can cause a cascade of other ADAS system failures.
In a previous article, we discussed the lack of organisation and standardisation of OBD 1 diagnostic systems, and in many ways, the situation around ADAS systems and their implementation is largely similar. For instance, unlike OBD II and the various SAE and ISO standards that underpin it, there are no standards in place in any automotive market in the world that prescribe or mandate how any particular ADAS system should be configured, implemented, calibrated, or integrated into any other system on any vehicle.
Thus, in this article, we will discuss various aspects of ADAS systems, as well as how ADAS systems are implemented on modern cars, but from a perspective that not many of us consider regularly. We will also discuss some of the things we need to look out for when we encounter ADAS system failures, but before we get to specifics, though, let us look at-
Thus, in some ways, the world of ADAS development and implementation is largely chaotic, with a knock-'em-down and drag-'em-out battle raging between car manufacturers to increase their market share. Of course, as with anything in life, there are exceptions to this rule, and mandated systems like stability control, traction control, and forward accident mitigation have prevented many accidents and saved many lives over the years. In addition, the automatic emergency braking systems that will soon be mandated in the American and other major markets will no doubt save many more lives.
However, from our perspective as technicians and mechanics, the problem remains the same. There are not only no standards that simplify and/or standardize the repair, servicing, and calibration of any ADAS system; there is also no way to be sure that we in the independent repair industry are performing these operations to OEM standards and specifications unless we obtain the relevant information directly from the manufacturer concerned.
Worse, though, while many manufacturers of aftermarket scan tools now offer dedicated ADAS calibration equipment, the problem with this is that all vehicle manufacturers can and do, update, upgrade, or otherwise change the implementation of some ADAS systems several times during a model's production run. As a practical matter, this means that calibrating a system like, for instance, adaptive cruise control on one model may differ dramatically from how it must be done on a new "face-lifted" version of the same model because the forward-looking cameras or radar transponder may have been moved to a different location.
To be fair to vehicle manufacturers, though, it must be said that most of them have greatly simplified the servicing and/or calibration procedures of at least some of the safety-critical ADAS systems on their products. Many calibrations now only require a simple static check to verify that all the components in a given system are working as intended, followed by a dynamic calibration by test-driving the vehicle in a prescribed manner in prescribed conditions for a prescribed distance. In some cases, calibrations like these can now be completed in under thirty minutes or so, when the same procedures used to take at least a couple of hours.
So while dynamic calibrations of some ADAS systems on some vehicles have taken much of the guesswork out of calibrating these systems, there are no guarantees that all future iterations of the same model will also allow for the dynamic calibration of ADAS systems that can be calibrated dynamically on current iterations, which begs the question of-
The world of industrial design turns on the close relationship between form and function, with form usually (but not always) following function*. We could fill a volume of how this pertains to car design, but in the interest of brevity, we’ll just say that in terms of function, a self-propelled device that can transport people would suffice, while in terms of form, one could say that a steel box with a wheel on each corner, and doors to allow people to get in and out of the box, would be ideal.
*For the purposes of this section, we will ignore super/exotic/hypercars, because with these vehicles, the relationship between form and image is vastly more important than the relationship between form and function could ever be.
In terms of refinement, one could add a reasonably reliable engine, a means to steer the wheels on at least one axle, a brake system to slow the box down, and some windows to allow the box's occupants to observe their surroundings. In fact, for a long time, cars were just that; dangerous steel boxes with engines, doors, wheels on each corner, and brakes that hardly worked.
We could fill another volume on the so-called “good old days” of car design, but suffice to say that the cars of decades past were more dangerous than modern cars by several orders of magnitude. Nonetheless, while using a modern car is still not the safest way of getting from point “A” to point “B”, the advent of advanced computer-aided car design strategies, safety ratings, and destructive crash tests have made modern cars about as resistant to accident damage as they are ever likely to be.
Moreover, the use of multiple materials has added significant strength and rigidity to the structures of modern cars, and the adoption of ABS and other ADAS-level systems makes it significantly less likely that an average modern car will experience accident damage in the first place, but what does this have to do with ADAS standardisation or the lack of it?
This is not an easy question to answer because explaining all of the reasons why standardization is not possible will take too long. Therefore, we will focus on the one aspect of the question that covers the most ground, so to speak, and which has to do with-
One of the problems for ordinary car enthusiasts and mechanics alike is that it is very difficult to keep up with which manufacturer owns which brands. Up to comparatively recently, Ford products were unmistakably Fords, but now, there is likely to be a fair amount of Mazda DNA even in relatively new Fords. The same is true for VAG- the larger VW group owns several major brands, most of which share only four or five so-called "platforms", with Lamborghini possibly being the only VAG-group owned vehicle brand that has a dedicated platform and design team.
Other examples include Chrysler, General Motors, and China-based Geely, who between them, own at least one dozen or so major brands- Fiat and Alfa Romeo in the case of Chrysler, and the division of Volvo that makes light vehicles, in the case of Geely. There are other still other examples, but we digress.
The point is that from a mass-production perspective, it makes a huge amount of economic sense to develop only a handful of platforms that each fall into a specific market segment, since developing dedicated platforms for each market segment every three or four years is a hugely expensive exercise. So, the trick to achieving economies of scale is to regularly dress up each platform with different front and rear ends, or maybe a slightly different roofline, or perhaps with boots stuck onto hatchback platforms to create instant sedans.
Exactly which model range is branded as what (and sold where), is a topic for another time, but based on many considerations that include consumer demand and preferences, some VW Golfs and Passats become instant Skodas or SEATs, and various Buicks and Oldmobiles become instant Holdens. The practice of rebranding vehicles is not new: it has been a standard (global) industry practice for decades, but there are too many examples of several brands sharing the same platform on the roads today to name all, or even most of them here.
Nonetheless, the advent of ADAS systems has made it just a little more difficult for car manufacturers to stick a boot onto a hatchback, change a two-door coupe into a four-door sedan, or change a front end to accept a redesigned grille, headlights, or restyled bonnet. While these things are relatively easy to do and cost a fraction of the price of developing a new platform, in practice, all changes must preserve the original platform’s rigidity, safety features, and NVH (Noise, Vibration, and Harshness) characteristics.
Let us take a practical example. Changing the headlights, grille, and bonnet of a German-made Passat to create a SEAT for the Spanish market, or a Skoda for the East European market may require the redesign of up to 100 (or more) individual body parts, many of which are structural components, and many of which determine the NVH characteristics of the platform.
Many car manufacturers do this routinely because this s a cost-effective way of creating "new" models. However, in many cases, these developments require that ADAS components like radar and/or lidar transponders, infrared sensors/cameras, optical cameras, and infrasound detectors be moved from where they were located on say, the original Passat, to new positions on the newly created SEAT or Skoda model. For instance, the radar transponder for the Passat’s adaptive cruise control may be moved from behind the VW badge on the grille (where they most commonly live), to a position behind the redesigned front bumper on the newly created SEAT or Skoda model.
Moreover, the new position may be offset from the vehicle's thrust line by varying amounts, depending on the actual model and other equipment that may be fitted to the front of the vehicle. Thus, since there are no standards that oblige vehicle manufacturers to locate specific categories of ADAS equipment in prescribed locations or positions on any vehicle, manufacturers are free to place any component on any vehicle wherever they want.
In the real world though, the nature of ADAS equipment requires that vehicle manufacturers observe some basic guidelines when they fit ADAS components, some of these guidelines being-
So by leveraging the economies of scale that flows from the ownership of many vehicle brands, the major car manufacturers realize enormous cost savings because with a minimal outlay of time and capital, any given ADAS system can be made to work on a wide range of makes and models over several generations. As a matter of fact, when it comes to rebranding modern vehicles, the only major problem car manufacturers have involves the development of make and model specific ADAS calibration procedures, which is the point where and how-
Due to limited space, we cannot discuss specific calibration procedures here, but we can do the next best thing, which is to highlight some of the things we need to look out for when we encounter ADAS system issues or experience issues with calibrating some ADAS systems. Let us start with looking at some things to look out for-
While most manufacturers locate sensors and microphones for Lane Keep Assist, Park Assist, Reverse Cameras, and Blind Spot Monitoring (among others) behind the rear bumper, some manufacturers place at least some of these components directly on the inside surface of the bumper. So to ensure that the bumper remains transparent for some of these sensors and devices, rear bumpers are typically manufactured to extremely tight tolerances concerning thickness, radii, attachment points, and especially, the maximum allowable paint thickness.
Unless you are an expert body repairer, you may not know that many car manufacturers forbid any sort of repairs to any part of any plastic bumper on any of their vehicles, simply because poorly executed repairs could, and sometimes do, prevent some sensors from “seeing” through the repaired bumper. This is especially true of repainted bumpers: while the paint thickness may not exceed the maximum allowable thickness, the type of primer and/or paint used to repaint the bumper could, and sometimes does render some sensors "blind".
Thus, if you experience ADAS calibration issues and you suspect that any plastic bumper may have been repaired and/or repainted, the best thing to do is to obtain your customer’s permission to refer the vehicle to an expert, and properly accredited body repairer to have the bumper inspected for signs of repairs or repainting.
Many vehicles use two optical cameras in their (among others) Adaptive Cruise Control, Forward Accident Mitigation, and Automatic Emergency Braking systems, and in most cases, these cameras are built into the vehicle in such a way that the vehicle has “binocular vision”. In simple terms, this means that the vehicle receives two images (one from each camera), which are then combined by complicated software to provide depth perception.
However, since windscreens are curved in two axes, the optical elements in each camera are corrected to compensate for the way light refracts through the curved windscreen directly in front of each camera. Put in another way, each camera looks through a part of the windscreen that had been “flattened out” by the modified lenses in each camera, in much the same way that glasses correct defects in human vision.
Unlike human vision though, the optical cameras in cars are aligned so that the centre lines of the field of view of each camera converge at a point a few hundred metres in front of the vehicle, at which point both cameras see the same image, but from a slightly different perspective. However, this happens only when a) a replacement windscreen is made to OEM specifications to ensure the correct curvatures in all directions, and b) when a replacement windscreen is fitted strictly according to OEM procedures to ensure the cameras “look” through the glass at precisely the same points as they did on the original windscreen.
Briefly, the problem is this; when the original windscreen was installed in the factory, the process used computer-controlled jigs and fixtures (some of which use laser guides) to ensure that every windscreen is fitted in exactly the right position. Glass replacement centres typically do not have the same equipment, and fitting a new windscreen on many cars is often a matter of gluing the windscreen down and hoping that everything works afterwards. There are exceptions to this of course, but for the most part, optical cameras must be recalibrated after a windscreen replacement.
In practice though, it is impossible to set up calibration targets a few hundred metres in front of a vehicle, so OEM calibration targets/equipment are designed to simulate the point at which the cameras' fields of view converge. Therefore, provided calibration targets are placed correctly, each camera will focus on a different part of the target, and complex software in one or more control modules will combine the two images to form a single image. That is the theory: in practice, while some aftermarket suppliers do supply these types of calibration targets, they have to be OEM approved. If they are not OEM-approved in terms of their colour, design, reflectivity, and even the material they are made from, it will be impossible to calibrate the cameras even if the new windscreen had been fitted exactly to OEM specs.
On a practical level, un-calibrated, or poorly calibrated forward-looking cameras comes with serious consequences. For instance, one or more control modules may disable not only the Adaptive Cruise Control system because the system cannot see clearly in front of it, but depending on the vehicle, other systems that may be disabled include the-
Note that while not all of the systems listed above depend directly on the forward-looking cameras to be calibrated to work, all of the above systems depend on either, or both, the autonomous steering and ABS systems to work to function as intended. Thus, if the Adaptive Cruise control system is disabled because it can't see in front of it, the ABS will be disabled as well, thereby causing a cascade of other ABS-dependent system failures- only some of which are listed above.
Nowadays, proper wheel alignment is about much more than extending the useful lives of tyres. Today, correct wheel alignment settings and accurate steering angle sensor calibration settings combine to form the proverbial cornerstone upon which the correct functioning of at least a dozen ADAS systems depend to work as both designed and intended. Depending on the vehicle, other factors that play a role to a lesser or greater degree include wheel size/diameter, rim offsets, un-sprung mass, spring and shock absorber compression and rebound rates, as well as the amount of free-play in suspension and steering components.
Experienced wheel alignment technicians will know that getting all relevant wheel alignment settings right on standard and undamaged vehicles usually does not present much of a problem. However, experienced wheel alignment technicians will also know that some suspension modifications, such as changing rim offsets, fitting lift kits and replacing resilient rubber bushings in suspension and steering systems with hard and unyielding polyurethane bushings often remove much, if not all of a suspension system’s ability to flex and self-adjust under extreme cornering, braking, and steering forces.
Removing or limiting this ability has several consequences, some of which have a direct impact on how well (or otherwise) systems like Stability and Traction Control react to sudden shifts in a vehicle’s weight. For instance, if a sudden evasive maneuver suddenly transfers much of the vehicle’s weight into the tyres, instead of into the suspension where the inputs could be processed by the Active Suspension Control system, the Stability Control System might not recognise that a potentially dangerous situation exists. Thus, the Stability Control System may fail to activate, thus allowing an accident to occur that could (potentially) have been prevented.
In these kinds of situations, the steering angle sensor plays by far the biggest and most important role, which is why the wheels on modern cars are always referenced to the vehicle’s centre (aka thrust line), which is in its turn, referenced to the steering angle sensor. Put differently, this means that if the wheels are properly aligned and the steering angle sensor is properly calibrated, the steering angle will communicate a “zero steering angle input” to multiple control modules, and the vehicle will follow a line that corresponds directly to the line that runs lengthwise through the vehicle.
Therefore, if all the wheels are aligned to the vehicle’s centre line but the steering angle sensor is not referenced to either the wheels or the vehicle’s centre line, the steering angle sensor will indicate an active steering angle input to multiple control modules, even if the vehicle is moving straight ahead. As a result of the indicated steering input, one or more control modules will do their utmost to steer the vehicle back to a zero (indicated) steering angle position, which could make it almost impossible for a driver to keep the vehicle centred in a driving lane, even on a flat road with no significant camber.
As a practical matter, the combined effects of a poorly calibrated steering angle sensor and a suspension system’s reduced ability to self adjust under some driving conditions can mimic the effects of, among other things-
This writer has lived through many bitter battles with customers over ill-considered suspension modifications that affect the operation of one or more ADAS systems, and you will no doubt encounter many such battles of your own during your career. However, while this writer cannot tell you how to fight these battles, he can do the next best thing, which is to recommend that you consider these issues as safety-critical issues that are best resolved with OEM level information and equipment, and to document every step of your initial inspection and subsequent repair steps. Doing this will save you many hours of arguing with customers, as well as many dollars in preventing expensive comebacks that should not occur, which leaves us with this-
The best advice this writer can offer when dealing with tricky ADAS issues is to forget the idea that ADAS systems on GM cars work this way, that ADAS systems on Ford cars work in another way, and that ADAS systems on Chrysler cars work in yet another way.
The easiest way to approach these kinds of issues is to think of each car as a unique vehicle with unique problems, regardless of its brand or model. While having at least a working knowledge of the technical underpinnings of ADAS systems and the relationships between them helps, you will arrive at the solution much sooner than you have otherwise if you consider the basics before you dive headfirst into a potential diagnostic rabbit hole.
In this context, the “basics” comprise checking for recent repairs to glass, bumpers, and body panels before progressing to checking and verifying VINs, software versions, and the availability of TSBs and other resources that address known problems. Only when all the numbers match and you are sure you are not dealing with updates and changes to a system that the manufacturer failed to mention to anyone, should you embark on an actual diagnostic process, but preferably not a diagnostic process that you found on YouTube.
From a safety perspective, it is critically important to obtain as much technical information about the affected system as you can get from official sources, which may be expensive, but even so, information bought from official sources is always cheaper than endless comebacks and interminable arguments with difficult customers.
