In Part 1 of this article, we discussed some circumstances that could lead to comebacks and unhappy customers, even though we may not be directly involved in the initial discussions between customers and the front office staff. Most of the time, we accept the information about customers’ concerns on work orders or job cards provided to us by service advisors as accurate and complete- until we discover that said information is neither complete nor accurate.
Note that we are not suggesting that service advisors provide us with defective information intentionally. Therefore, if we take a step back and think about the fact that some customers cannot express the faults and symptoms they see or experience on their vehicles clearly or adequately, we might realise and appreciate the fact that the information we do sometimes get, is all the information a service advisor had to give us.
Moreover, when service advisors who are not mechanics undertake a vehicle inspection or perform a test drive may not recognise or experience some or all of the symptoms a customer experiences. Alternatively, when they do recognise symptoms, they may not relate observed symptoms to the problem the customer is complaining about, especially when faults occur intermittently or only under certain conditions.
Over the past 40 years or so, this writer has observed many instances of service advisors in his employ providing technicians with seemingly inaccurate or incomplete information about customer concerns, but then again, connecting symptoms and faults is not their job. This is our job as mechanics and technicians, but if the truth were told, most, if not all of us have experienced that sinking feeling when we are presented with a vehicle with intermittent faults. Sometimes, we don't know where to begin a diagnostic process, but on the upside, such moments provide us with the perfect opportunity to take a step back and recognise that sometimes-
Much has been written about the ever-increasing complexity of modern cars over the past two decades or so, and we don’t need to add to this topic here, but with that said, what exactly does the concept of “increasing complexity” mean in the context of our daily lives in car repair workshops and service bays?
There are many possible answers to this question but if we reduce the question to its simplest form, we can say that the single most complex systems in modern vehicles are their electrical systems and the programming that makes these systems work. In practice, modern high-end vehicles run off about 150 million lines of computer code, while by way of contrast, modern heavy commercial passenger aircraft operate safely and reliably with only about 15 million lines of code- including their autopilot and instrument take-off and landing modes.
So, why do we mention this? We mention this to illustrate the point that the amount of information contained in 150 million lines of code is so vast that no human being can form a mental picture of how everything on a modern vehicle works. We can illustrate this further by saying that the dozens of control modules in a modern high-end vehicle collectively perform several hundred million calculations and operations every second, even if the vehicle is just cruising in a straight line at a steady speed, while ADAS systems like Adaptive Cruise Control, Stability Control, Blind Spot Monitoring, and Lane Keep Assist are in operation.
Given the above numbers, it is hardly surprising that we sometimes don't know how some systems on modern vehicles work, which is particularly pertinent to how we approach or should approach tricky diagnostic challenges and problems on vehicles and systems we are not familiar with. We all have different ways of doing things, and it is therefore not for this writer to tell you how to go about diagnosing faults on unfamiliar vehicles, but in the context of potential comebacks, the guiding principle should always be this-
Do not work on unfamiliar vehicles without OEM-level service information
Of course, there are exceptions to this rule since few competent mechanics will have trouble diagnosing generic faults like oxygen sensor issues, air/fuel metering issues, or most fluid leaks and the like, even on vehicles they have never seen before. However, many non-generic issues are another matter entirely, and while it is easy to say don’t do this, that, or the other thing, the problem is that many among us are employees and are, therefore, not in a position to refuse to work on a particular vehicle without access to OEM-level service information.
On the other hand, if we are to avoid the possibility of a comeback, we really should not attempt to diagnose and repair any issue on any unfamiliar modern vehicle unless we have access to up-to-date and reliable repair and service information, such as wiring diagrams, waveform libraries, and TSB archives. So, what to do?
This writer will be the first to admit that there are no easy answers if employers do not provide access to service information via the data sharing law or through some other means, such as subscribing to third-party sources of service information, which could be pricey. In fact, one-time access to some third-party sources of information for a limited time currently runs to 20 US dollars or more.
However, since the alternative to using OEM-service information to diagnose and repair issues on modern vehicles today amounts to inviting trouble in the form of comebacks and potentially ruinous financial losses, let us look at-
One surefire way to avoid comebacks is to refuse to work on a vehicle if there is no OEM-level service information available for it, but that is easy for this writer to do because he is self-employed and is, therefore, free to accept or decline any job.
However, if you are an employee in a workshop, you do not have this freedom but there are nevertheless some things you can do to improve your chances of finding faults on unfamiliar vehicles. Based on this writer’s observations over many years of how successful technicians work, these things include the facts that successful technicians and diagnosticians -
Do not use diagnostic flow charts
If you are new to the car repair industry, you should know that car manufacturers design diagnostic flow charts to help mechanics resolve problems in the shortest possible time, as opposed to helping mechanics find the root cause(s)of problems. In short, while diagnostic flow charts might help you resolve an issue, they never help you find the root cause of the problem.
Always replicate the fault
Put simply, it is impossible to fix something you a) do not understand or b) have not seen or experienced for yourself. Therefore, it is crucially important that you do not attempt to diagnose, test, or repair anything before you have verified the existence of a customer’s complaint or concern by replicating the problem and its symptoms.
Of course, how you do this depends entirely on the nature of the problem, but the point is that you can only begin to formulate a diagnostic strategy after you have confirmed that a) a fault exists and b) the symptoms you observe match the symptoms observed by the customer. This might come across as preaching to the converted but this writer has observed many technicians doing things the other way around, which leads to confusion, misdiagnoses, wasted time, and comebacks more often than not.
Colour code wiring diagrams
Wiring diagrams are no longer nice-to-have items- they are now required diagnostic tools if you want a fair chance of resolving complex electrical problems. However, one way of turning wiring diagrams into super diagnostic tools is to print them out, find your area of concern/interest, and then use fine-tipped highlighters to trace out relevant circuits from the source of power through all switching devices and on to include all affected consumers.
This writer uses red to outline permanently live wires, green to outline ground circuits, blue to outline switched circuits, neon pink to mark control modules associated with within circuits of interest, and orange to mark out relays and switches, which has the effect of creating a kind of bird’s eye view of the entire area of interest on the diagram. The biggest advantage of this practice is that it prevents one from becoming distracted by unrelated circuits on the diagram, which greatly reduces time spent on deciphering complex circuits.
While interactive wiring diagrams displayed on computer monitors do much the same thing as manually tracing out circuits, it is rarely possible to display the entire area of interest on a wiring diagram at a scale that makes tracing circuits from beginning to end easy or practical.
Make extensive use of information systems
We stated elsewhere that it is becoming increasingly difficult to repair modern vehicles without referring to OEM service information but in some cases, it is actually impossible to perform some service or repair procedures without referencing OEM service information. We can list manysuch examples here, but the following two will suffice-
It is impossible to perform the above procedures correctly without the required service information, and although you could obtain the information you need from car manufacturers under the data sharing law, this writer has had some very frustrating and time-consuming experiences in attempting to obtain up-to-date service or repair information from some manufacturers via this route.
Of course, your experience(s) may differ, but overall, a better way to obtain OEM service information is to buy it from one or more third-party vendors, which this writer has been doing for many years. It should be noted, though, that OEM service information systems are not created equal, but the service/system this writer uses offers the following advantages, albeit at a price-
Of course, all of the above comes at a hefty-ish monthly subscription, which, if you were to pay it out of your own pocket could make a noticeable dent in your take-home pay. Then again, making a mistake because of a lack of relevant service information could result in a comeback that might have devastating financial consequences for both yourself and your employer, so in the context of avoiding comebacks, wouldn’t you want to buy service information if you can’t get it in any other way?
Thirty years or so ago, car repair manuals ran to several hundred pages, but today, repair manuals can run 5000 or more pages, typically excluding wiring diagrams and diagnostic flow charts, which raises this question-
Well, no, not entirely. We are all human, and we can all make honest mistakes, but then again, if we are armed with up-to-date service information, we can greatly reduce the chances of making mistakes, honest or otherwise.
There is no doubt that there is a direct link between the chances of some workshops seeing significant numbers of comebacks and the level of access technicians and mechanics in such workshops have to accurate OEM-level service and repair information.
Moreover, on a practical level, no amount of experience can compensate for a lack of access to service information, so if push came to shove, paying for service information from your own pocket if your employer won't pay for it is the fastest way of becoming the diagnostician you always wanted to be, but more importantly, the diagnostician you need to be to remain relevant in an increasingly competitive industry.
