Mechanic Connection: Keeping Up with Technology

Mechanic Connection: Keeping Up with Technology

Automotive technology has advanced steadily in the last 50 years, but keeping up with it involves the tech’s mind and experience as much as it does scan tools and the Internet.

An impression shared by the trade press and the motoring public is that the modern technician keeps up with technology by attending the latest training classes and absorbing through rote memorization its latest intricacies. It’s sad to say, but nothing could be farther from the truth because, in the real world, the only available instructor is most often the technician himself. As such, learning about complex electronic operating systems is a daily, on-going process of reading, experimentation and adaptation.

For today’s ASE Certified Master Automobile Technician (CMAT) with the L1 Advanced Engine Performance certification, keeping up with information technology is like living in a world where the normal rules of life are changed to suit the moment. Ten years ago, for example, a technician was taught that observing oxygen sensor waveforms on a lab scope would provide the information needed to detect fuel control and ignition failure problems.

That rule suddenly turned into an information “curve ball” when the Onboard Diagnostics II (OBDII) engine management systems came into being in 1996. In this single act, the previous methods of oxygen sensor analysis were replaced by a mathematical model contained in the Powertrain Control Module (PCM)’s electronic operating strategy. Overnight, many scan tools were designed to measure six or more different operating parameters for oxygen sensors. Again, the technician experienced a “curve ball” because the PCM became the final authority on oxygen sensor analysis.

But now, technicians are discovering that a flaw in the PCM’s math program can cause a false oxygen sensor diagnostic trouble code. Recently, this new learning curve took place for me when a 2000 Subaru 2.5-liter engine returned to my shop one year after replacing the air/fuel sensor with the same trouble code as before. The only way I could find a rationale for the trouble code was to contact my technical hotline and speak with an experienced Subaru technician who confirmed my suspicion that this failure was indeed a programming, rather than hardware, issue. In one stroke, many years of learning had just been rendered obsolete by a mathematical mistake in the auto manufacturer’s engineering department!

Between 600 and 1,700 different vehicle models are appearing on the domestic market each model year. Either extreme is daunting because, for the independent shop technician, that’s at least 600 more new operating systems and failure patterns to learn.

To illustrate, I recently inspected a 2000 Ford Focus with six different operating system problems including an intermittent trip meter display, no power door locks, no remote rear hatch release and no rear wiper. To “educate” myself on how each of these systems work, I printed a dozen pages of wiring schematics, power distributions and ground distributions. Afterward, I spent an hour figuring out how each operating system was related to the other.

Without touching a wrench or a test light, I used the above information and determined that the wiring harness at the rear hatch hinge had a number of open circuits. The body-control problems became an open-ended repair that required some component replacement before further testing could be done.

As for the actual diagnosis, I used a scan tool to retrieve three body-control trouble codes to confirm that the rear wiper switch had a short-circuited wire. Two additional codes indicated that the door lock sensors weren’t functioning correctly. I “polled” the PCM, Anti-Lock Braking (ABS,) Airbag (SRS), Anti-theft (PATS) and Body Control (GEM/CTM) modules to see if they were communicating with each other. All of this diagnostic procedure, mind you, was on an entry-level station wagon with manual roll-up windows! While such a situation was unheard of six short years ago, it’s a common occurrence today.

The printed word rules the modern training climate because formal training is required to teach people the basics of vehicle repair as well as keep veteran technicians abreast of current technology. An auto mechanics program contains more than 1,000 clock hours of classroom instruction and requires thousands of pages of reading just to learn the basics of auto repair.
Once at the journeyman level, the new technician will usually become an ASE Certified Master Automobile Technician (CMAT) with the advanced engine performance certification (L1) in engine management electronics. From this point on, the technician will attend advanced-level classes taught by recognized industry experts. He will also begin to network with other advanced-level technicians through Internet groups like the International Automotive Technician’s Network (iATN). In addition, he may subscribe to various technical hot lines and expert-level Web sites, both of which serve as de facto training sessions that are available when the technician encounters an unfamiliar operating system.

I recently had a 2004 Dodge Dakota equipped with a 3.7-liter engine come into my shop with the “Check Engine” light on, but with no noticeable driveability complaints. Using my scan tool, I retrieved a P0116 diagnostic trouble code, which indicates an “engine coolant temperature circuit or rationality problem.” Going back to basic operating strategy, the PCM is looking for a specific temperature rise in coolant temperature during a specific length of time. Several diagnostic possibilities existed, including a bad thermostat, coolant temperature sensor, faulty wiring or PCM.

As with any diagnostic trouble code, the proper procedure is to avoid re-inventing the diagnostic wheel by researching technical service bulletins that pertain to a driveability trouble code. By researching the TSBs on this vehicle, I found that the P0116 DTC was, in all likelihood, a false trouble code that might be better addressed through reprogramming the PCM rather than replacing hard parts.

Just to make sure, I stepped away from the TSB’s diagnostic procedures and verified the coolant temperature sensor and thermostat operation by simply graphing the engine warm-up time and peak operating temperatures on a graphing scan tool. Here again is a modern repair scenario in which in-shop experimentation has taken place of formal training.

As illustrated above, it’s not unusual for a top-drawer technician to spend several hours researching technical service bulletins and pattern failure Web sites just to gain insight on an unusual problem. Unfortunately, our current shop procedures are based upon diagnosing the simple electrical systems of 50 years ago. In reality, modern vehicle electronic systems are far too complex for anyone but the most specialized technician to memorize in principle, let alone detail. Consequently, many research hours are left unbilled as “unproductive labor” when, in reality, research time is an integral component of the learning and diagnostic process.

More often than not, parts manufacturers and distributors fail to recognize that the gap between low-tech and high-tech auto repairs is widening. On the one hand, a majority of shops are emphasizing preventive maintenance, which is a less-skilled and information-intensive line of work. On the other hand, a minority of better-qualified shops are emphasizing technical capability, which is a time-consuming, capital-intensive undertaking. As a result, many high-tech shops are finding that the soaring costs of equipment and information are making them less competitive in the general service markets.

But technology marches on. Although the new hybrid vehicles have become the latest trend in motor vehicle technology, few buyers realize that, with the exception of the mechanical linkage between the steering and front wheels, all other functions in the modern hybrid are electronically controlled. Similarly, automotive technology has advanced far enough to replace traditional hydraulic power steering and brakes with full electrical/electronic systems. The same can be said of heating and air conditioning and all other body control functions.

The dividing line between low- and high-tech repair shops, of course, is the learning curve required to master a variety of new technical and empirical information. Without accommodating that learning curve, the independent repair shop will quickly become a shrinking image in the rear view mirror of modern technology.

Gary Goms owns and operates Midland Engine Electronics & Diagnostics in Buena Vista, CO.

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