In-shop diagnostic tools a vital link for lasting repairs

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“The days where a technician can use a cheap handheld scanner to diagnose complicated electrical issues is gone,” says Dustin Carnes of Diesel Laptops.

TORONTO, Ont. — Modern trucks are not known to keep problems to themselves. If temperatures or pressures stray beyond a particular range, the dash begins to light up like a Christmas tree. Telematics systems fire warnings to fleet managers and OEMs alike, sometimes before the wheels stop turning.

But in most cases, the insights are limited to snippets of information. Full stories – the details that are needed for a lasting repair – largely remain the domain of in-shop diagnostic tools.

Consider a warning that draws attention to low boost pressure, explains Dustin Carnes, training manager at Diesel Laptops, a supplier of diagnostic software. “There’s 20 different things that could be causing that low boost.” Maybe the root cause is a bad turbocharger actuator, or a biased sensor.

To compound issues, the warnings are not always triggered one at a time.

“You’ve got to be able to find who started it, who started squawking first,” says JPRO’s chief technology officer, Dave Covington, referring to multiple warnings that can be triggered almost simultaneously. “All these ECUs on these new trucks are very reliant on one another. Your transmission and your engine are no longer separate entities. Your transmission can affect your engine and vice versa. And, of course, your brakes affect everybody and everything on the truck.”

But the latest generation of diagnostic tools can log multiple data items and observe all the electronic control units at the same time. And the benefits don’t end there.

“If you have a cell device or a wifi device or satellite device that’s not functioning properly, you can’t talk to the truck,” Covington adds, referring to one limitation of telematics. “The good thing about a [diagnostic tool’s] wired connection is you can go in and patch a wire, fix a wire, crimp a new pin on, and always talk to that truck.”

Telematics systems do a “phenomenal” job when it comes to letting fleet managers monitor their vehicles, but there are limits to the amount of data that will be transferred, agrees Kristy LaPage, business manager of Mitchell 1’s commercial vehicle group. “It’s just too much data on the vehicle being read for it to be transmitted.”

She has heard telematics systems described like Fitbit personal fitness trackers. Using a similar analogy, in-shop diagnostic tools are more like the monitors left in the hands of medical specialists.

Monitoring your pulse during a workout is one thing. Identifying the need for a bypass is something altogether different.

One challenge can involve simply establishing a connection, says JPRO product manager Jason Hedman.

Diagnostic tools are evolving

Still, increasingly complex vehicles and their growing number of sensors have also required the tools themselves to evolve.

“The days where a technician can use a cheap handheld scanner to diagnose complicated electrical issues is gone,” Carnes says. “OEMs have gotten very specific with the types of tests that need to be performed, and the types of information that must be monitored is very control-module specific.”

“Just getting the data off the truck is a hassle,” says JPRO product manager Jason Hedman, referring to the way some manufacturers moved the pins and protocols on J1939 Type 2 green connectors … sometimes without telling those who develop the third-party tools.

It’s just one example of the challenge suppliers face in the push to ensure their tools continue to advance.

Freeze frame a moment in time

One of the key features to emerge in the race to address ghosts in the machine – codes and warnings that appear and disappear for no particular reason – comes in the form of “freeze frames” that can capture a moment in time, comparing pending and active codes alike.

“With scan tools I can hook the vehicle up and I can see where the different fault codes are happening, and at what time, and from there I can kind of start identifying different parameters around when the fault code happened. ” LaPage says. “The fact the vehicle talks back to us so much better now, that is one of the most amazing things.”

Carnes worked at an International dealership for 12 years, and can remember trucks that would arrive along with a half dozen inactive fault codes and reports about a specific driver complaint. “There’s no active code telling you to go to a specific area,” he says. But freeze frames can report when a code was first logged, helping to track down a root cause.

It’s all about a process of elimination. If a driver reports that a code is activated when a vehicle reaches a specific operating temperature, for example, a code that emerged when coolant temperatures were sitting at around 90 degrees likely isn’t the information that will guide the necessary repair. “It’ll help you narrow down certain issues when you don’t have a lot of other data,” Carnes says.

Of course, there’s a difference between data and information that shop teams can act upon.

“It’s [about] more than giving a technician a wall of data and a wall of faults and saying, ‘Here, go figure it out,’” Covington says of the ultimate goal, referring to the layers of data that can be accessed in an advanced tool.

While measuring the levels of soot in an aftertreatment system is important, shops also need to know what the levels mean within a particular system, and ultimately what actions are required, he says.

“It’s not just the repair that you’re looking to do. It’s the preventative stuff. When to run a regen and when not to run a regen,” Hedman agrees. It’s why he found himself cringing as he sat through a presentation where a fleet manager discussed regens that were completed every time a diagnostic tool touched a truck, whether the lamp was lit or not. “That’s a waste of time, fuel and money right there … at least in my eyes.”

Advanced diagnostic tools boast plenty of capabilities, but they also require extra training to use them.

Advanced diagnostic tools require extra training

While diagnostic tools can deliver deeper insights than ever before, mechanics still require training in how to use them to their full potential.

“There’s a huge gap of skill level when it comes to that area,” Carnes says. “Today’s trucks are getting more and more complicated pretty quick, and you’ve got a generation of technicians that have not had to use a computer.”

Some of them even avoided such tools until the last possible minute. LaPage remembers the “mass exodus” of automotive mechanics who left to work on diesel equipment tools when digital diagnostic tools became the norm in light-duty shops.

“You can’t do this job anymore without having an electronic background, or learn it as you go,” LaPage says. “The way of thinking has had to change. It’s no longer just turning a wrench. Now it really is sitting in front of a computer or laptop or scan tool and being able to read what that  vehicle is saying to you.”

It all places a greater emphasis on related training into how to use the tools.

“Knowledge of the vehicle systems to get connected, run tests, changing settings, and overall usage is paramount,” Carnes says. But shop personnel have been known to complain about missing features on a diagnostic tool only to discover that they simply didn’t understand how to access all the different functions.

Diesel Laptops tries to fill the gaps with weekly webinars that illustrate steps such as how to complete a connection, while a support team of retired diesel technicians is on hand to walk teams through the challenges.

“You’ve got to have as many avenues to reach them as possible,” Hedman says, referring to the training approaches that shops should look for when deciding on a supplier of diagnostic tools. “Tools need to be intuitive to begin with. You want people to want to use it. You also want to have tools that have capabilities built in to help train them.” Videos, slides, user guides, and “virtual trucks” built into the tool in the name of offering hands-on training can all help.

The small shop challenge

The right diagnostic tools can certainly put an independent shop or small fleet on a level playing field with a dealership network when it comes to diagnostic work. But it will be difficult to find all the tools that are necessary without breaking the bank.

“Dealers absolutely have a huge advantage over the smaller third-party shops and smaller fleets,” Carnes admits. “The more advanced these vehicles are becoming, the more proprietary each system is getting. And unfortunately, OEMs are trying their best to keep proprietary information to themselves.”

Many high-end tools will still bring the shops “very close” to the dealer experience, he says. Operations deal with remaining gaps by deciding the nature of specific work that might be sent elsewhere.

But for the work that remains within their domain, there are tools to help.




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John G. Smith is the editorial director of Newcom Media's trucking and supply chain publications -- including Today's Trucking,, TruckTech, Transport Routier, and Road Today. The award-winning journalist has covered the trucking industry since 1995.

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