Auto Service World
Feature   March 1, 2008   by Mike Cleary

Strategies for Diagnostic Success

What does it take to become an expert automotive diagnostician, or diagnostics technician? It is a question that has been asked and/or discussed countless times throughout the years. Through time, I h...

What does it take to become an expert automotive diagnostician, or diagnostics technician? It is a question that has been asked and/or discussed countless times throughout the years. Through time, I have compiled my own set of criteria to answer this question. I myself am a work in progress, just like every other technician out there. We never stop learning. It is a career-long journey. Let us explore some of the things that can be accomplished on the road to becoming an expert in automotive diagnostics, whether it is driveability diagnostics, or diagnostic situations dealing with body and/or chassis electricity or electronics.

In addition to the technical aspects of this topic, which will be discussed in a moment, there are a number of issues of a personal nature that a technician can accomplish in order to facilitate the path to diagnostic success.

A career in the automotive repair business is a very humbling experience. Every now and then we all work on a vehicle which is difficult to diagnose and which brings us back down to earth. This vehicle is always only as far away as the next assignment. Ego is one big detriment to being successful in diagnostics. Learn to be humble. Realize that no one knows everything. Too many times techs are afraid to ask for help or consult resources because they are either afraid or too proud to admit they don’t know something. Learn from other technicians who you recognize are more successful than you and don’t be afraid to ask them questions. Listen closely when they answer your questions. The great techs are always willing to spread their knowledge and experience with someone who is eager to learn.

One characteristic of humility is the ability and willingness to recognize your weaknesses. Determine which areas of the vehicle you are technically weak in, such as the brake system, or air conditioning system, or electrical system, and so forth. Then get the training you need to improve. Invest in yourself, both from a time investment standpoint and a monetary one. Spend time reading every automotive publication available. Subscribe to automotive industry trade publications. They have a wealth of information in them, and some of them you can get for free. Remember, the one thing that can never be taken away from you by anyone is the knowledge that has been

gained along this journey. As your career progresses and you move from one job to the next, or advance to the next position at the shop you are employed at, that acquired knowledge travels with you.

Speaking of training, resist developing the attitude that the employer should pay for all the training. Some employers will, while others will not. I know this is a controversial subject, but remember, the knowledge you gain from training is yours to keep forever. Work out a compromise, if needed, with your employer regarding the training expenses so that it is a win-win situation for both of you. Realize that even if you learn only a limited amount of information from a class, the few things you learn may save you a lot of money (i. e. time and frustration) in a difficult diagnostic situation. You get what you pay for.

Remember the three “Rs”: reading, writing and arithmetic? Reading, writing, and math skills are a necessity, not a luxury. If you recognize you have a weakness in one of these areas, make an effort to strengthen your skills in that subject. Just one case in point to illustrate their importance: dealership warranty clerks rely on explicit, detailed, clearly written repair information from their technicians in order to properly calculate warranty billing operations on a repair ticket. If the warranty clerk cannot read and/or understand the documentation written by a technician working on a flat rate compensation system, or any type of productivity bonus system, it may affect the way the ticket is billed out, adversely affecting the amount of pay which is due the technician for that particular repair.

Also along this line of thought, as vehicle technologies become more complex, it becomes increasingly difficult for automobile engineering departments to write repair manuals in simplified language. As the technology has become more advanced, so has the reading skill level required to properly comprehend the information. Reading comprehension skills are a definite asset.

The final thing to discuss when speaking of personal issues is mistakes. Don’t be afraid to make a mistake. A quality diagnostic tech is never afraid to make a mistake, because fear is crippling when it comes to performing any kind of diagnostics, particularly a diagnostic scenario of a highly technical nature. Realize that you will make mistakes. All technicians do, even the great ones. That said, the great techs always learn from their mistakes. All of the great driveability and electrical techs have these qualities.

Let’s move on now to the technical aspects of this topic.

Remember the ultimate goal as a technician: repair the car in a timely fashion. With this in mind, the following guidelines should be observed: Understand the basics. They are the building blocks to success, whether it be basic electricity, basic engine fundamentals, or others. For instance, you can’t make repairs on advanced vehicle electronics systems if you don’t have a thorough understanding of electricity. If you feel the need, take a training course again as a refresher. It’s amazing how many things were forgotten or misunderstood the first time through the course.

Avoid “pattern failure diagnostics.” Resist the temptation to think, “Well, the last couple of instances where I had this symptom on this particular vehicle it needed a (insert name of part here), so I think that part will fix it again this time.” This particular diagnostic strategy will eventually lead to trouble. In order to avoid this, develop your own personal diagnostic strategy and thought process which is comfortable for you, works best for you, and allows you to become successful. Note the emphasis on the word “you.” Don’t try to adopt someone else’s strategy just because they tell you it is the best one for you or because it is the one you are told to use. If you are not comfortable with it you will ultimately fail. Developing a strategy that is comfortable for you and works well for you will also limit your chances of making mistakes. There is nothing wrong with trying to emulate a successful diagnostics technician, but his diagnostics strategy may not be the right one for you.

Don’t “over test,” use appropriate equipment and procedures. Don’t make the diagnostic process more cumbersome than it needs to be. We all know the limitations of an ohmmeter, but if you have a solenoid, for instance, that has an open in the winding, you don’t need to set up your scope to diagnose that. Sure, you would find the open winding with a scope, but which piece of test equipment is quicker and easier to use? Keep your diagnostic process as simplified as possible.

Don’t try to memorize anything-your experience will dictate your memory. You will find yourself remembering (very different from memorizing) details about vehicle repair procedures (whether it be torque specs, bearing clearances etc.) as you repeat these operations on the same vehicle over and over again. This will happen without you realizing it. It is human nature. Trying to memorize details such as these is both counterproductive and a waste of time. Assemble for yourself a handful of binders which you can insert index tabs into and keep notes about certain repairs you have performed.

Then categorize them by that particular part of the vehicle, such as engine, transmission, electrical, ABS, and so on. Then when you need to find this info again it will be readily available.

With this in mind, develop a database on known “good” vehicles, so you have information to reference when a vehicle comes in with that particular problem, such as a stumble during tip-in. For instance, if you suspected an issue with the throttle pos
ition sensor, you could refer to the voltage readings you had compiled on a vehicle that was running properly, and then check to determine if the voltage readings being observed on the vehicle with the stumble corresponded with the information you had from the properly running vehicle to determine if the throttle position sensor was the cause of the stumble.

The other database to compile is to take a vehicle that is running properly and simulate failures on that vehicle. Then record the appropriate voltage data for the specific sensors and actuators involved so that when a vehicle comes in with similar symptoms, you will know what data is “good” data, and which data is “out of range.”

Finally, gather technical resources and don’t be afraid to consult them as required. As stated already, nobody knows or remembers everything.

Realize that it takes years to become a great diagnostics technician. Don’t get frustrated by your failures. Following the guidelines previously mentioned will help you attain your goal. Remember, it is your responsibility alone to work at achieving this goal. Through hard work and perseverance you will eventually attain it.

Now you’re dangerous.


Mike Cleary is an eight time award winning Ford Motor Company Certified Senior Master Technician and Powerstroke Engine Specialist. He has served on two separate Ford National Technician Advisory Boards, and received national recognition from Ford Motor Company for his contributions to Ford as a field technician involved in improving the 6.0L Powerstroke Engine Program. He has been a member of the Society of Automotive Engineers since 1980.

He currently owns his own shop, Cleary Automotive, specializing in high tech driveability and electronics repairs on Ford vehicle systems. He has 31 years of continuous experience as a hands-on automobile technician in independent shops (19 years) and dealerships (12 years). He can be reached at his web site at www.atsstraining.comor at

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1 Comment » for Strategies for Diagnostic Success
  1. thanks for the great insight. very helpful.

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