Proper equipment, information, education, and experience are the main elements...

Proper equipment, information, education, and experience are the main elements required
to avoid an improper diagnosis.

Photo: Getty Images 

Unplanned downtime can have significant implications for fleet operators and their customers who depend on timely deliveries. 

“Operators can be out thousands of dollars a day when they experience unplanned downtime. The impact on smaller operations can be even greater. They are less likely than larger fleets to have replacement vehicles on hand to make scheduled deliveries or work on a jobsite,” explained David Pardue, Mack Trucks vice president of connected vehicle and contract services.

Why Does Truck Diagnostics Matter?

Diagnostics are extremely valuable to the truck fleet operator to ensure that vehicles keep running. 

“It is not uncommon for a fleet to have support vehicles for carrying out daily operations. These vehicles may include cars and light trucks for general travel and light deliveries and medium-duty trucks used for maintenance and local haul purposes. These vehicles also need to be maintained and repaired. Without the capabilities to work on these vehicles in-house, the fleet will need to outsource this work,” said Kristy LaPage, business manager, Commercial Vehicle Group for Mitchell 1.

The average light- and/or medium-duty truck fleet is likely using their equipment to support the main aspects of their business. 

The Competitive Edge: In-House Fleet Maintenance

“Unlike some of the major large-scale heavy-duty trucking fleets which can have dedicated service, maintenance, and fleet managers, light- and/or medium-duty owners may not have the capacity to address every fault code, dash lamp, or driver statement about their vehicles,” said Aparna Venkatraman, director of digital product management for Cummins Inc.

Remote, telematics-based diagnostics solutions notifies fleets and equipment owners of prioritized fault codes and can recommend solutions to resolve the issue. 

“This communication helps customers filter out some of the noise and provides guided solutions to optimize equipment use and health,” Venkatraman added.

Vehicles are the backbone of the fleet. Without the ability to properly diagnose them, fleets are losing uptime. 

“This loss of uptime means a loss of productivity and profitability. When fleet vehicles aren’t operating at peak efficiency, the fleet has added costs in fuel and time (assuming that the vehicle is even running enough to function at all). With a proper and efficient diagnosis of an issue, the trucks can be back functioning and producing as expected,” said Tom Kraemer, account manager for Snap-on Business Solutions/Nexiq Technologies.

How to Avoid Improper Diagnostics

Once you understand the value of truck diagnostics, the next step is ensuring that you don’t make basic mistakes. 

Having the right tools for the job AND knowing how to use them is essential efficient truck...

Having the right tools for the job AND knowing how to use them is essential efficient truck fleet maintenance.

Photo: Getty Images 

“Access to information is critical. Often a failure code is initiated on a component, and while that component may have suffered a failure, the root cause may have come from another area. Having access to the diagrams and accurate procedures allows the tech to have a full view of the truck, thus giving the tech the ability to diagnose and repair the actual failure as opposed to what may be simply the symptom,” said LaPage of Mitchell 1.

Proper equipment, information, education, and experience are the main elements required to avoid an improper diagnosis. 

“Without the proper diagnostic equipment, the technician can only guess as to what the real issues with the truck might be. The technician is then left to troubleshoot an unknown issue, which requires more time than if they had a path to start with. Suppose they don’t have the information necessary to troubleshoot a concern. In that case, they are left guessing where to go next or what systems interact with one another,” said Kraemer of Snap-on Business Solutions/Nexiq Technologies.

Within truck diagnostics, there are many times a technician will have a fault for a system and, for example, needs to diagnose the exhaust gas recirculation (EGR) system first as that could be causing the Variable Geometry Turbocharger (VGT) to operate incorrectly. 

“The education relates to all of the points; if the technician does not have the experience, or education, on a system, it is going to take a lot longer to figure it out each time. If they do not know how to operate the diagnostic equipment, it will take them longer to learn it. If they do not know where or how to find the required information, that will also take extra time,” Kraemer added.

Common Diagnostic Problem Areas

Multiple mistakes can lead to improper diagnosis. 

“Some of the primary reasons for an improper diagnosis include not having service information, not having adequate diagnostic equipment, taking shortcuts based on assumptions, and lack of diagnostic knowledge,” said LaPage of Mitchell 1.

Another common issue when dealing with vehicle diagnostics is general vehicle performance awareness. 

“With the increase in dash-lights associated with aftertreatment systems and on-board diagnostic capabilities, more information is presented to an operator, owner, or service manager than previous generations of products. Cummins offers dash lamp indicator reference cards available for download, and the owner’s manual outlines the respective dash lamps and what they mean,” said Venkatraman of Cummins Inc.

The use of connected diagnostics can provide equipment owners and fleet managers with real-time equipment updates so they can effectively manage operations and minimize impact to the business. 

“When a fault code, or lamp is not illuminated, but a troublesome symptom is present, Expert Diagnostics System (EDS) allows technicians to troubleshoot symptom related issues. With guided step-by-step troubleshooting EDS can help resolve hard to diagnose complaints accurately, the first time,” Venkatraman added.

Anytime a truck or vehicle is back in the shop for a comeback or misdiagnosis it is costing the owner/operator money. 

“The cost is accrued from the vehicle not being in service plus the requirements to deliver it back to the shop. It may require two or more drivers to deliver the vehicle to the shop or a tow (both of which can be expensive). Then, the vehicle is tied up for however long it takes to figure out the true issue/concern. In addition, there may be -additional costs for subsequent repairs, as well as the costs associated with the previous session that did not fix the problem in the first place,” said Kraemer of Snap-on Business Solutions/NEXIQ Technologies.

Diagnostics are extremely valuable to the

truck fleet operator to...

Diagnostics are extremely valuable to the
truck fleet operator to ensure that vehicles
keep running.

Photo: Getty Images 

The Bottom Line

The value of ensuring proper truck diagnostics is undeniable. 

“It’s important to remember that the diagnostic tools today not only help techs ‘hear’ from a truck when it has a breakdown, but also help techs perform regular diagnostic checks to detect minor issues that when caught early, can help to prevent or reduce costly repairs later,” said LaPage of Mitchell 1.

Having the proper tools for the job, and being able to use them quickly and easily, is extremely important. 

“Having trusted and reliable OEM-approved data is also extremely important (since you know that the data is good and you don’t have to be concerned about the validity of the information that you are using to evaluate the concerns with the vehicle),” said Kraemer of Snap-on Business Solutions/NEXIQ Technologies.

And remember: Trucks never breakdown where it is convenient. 

“Having a tool that you can take anywhere, and immediately read the vehicle, saves the most amount of time and money. This is especially true if you encounter issues when reading the vehicle, which only adds frustration to the technician and delays. The technician does not want, nor need, to hunt for a power source or make sure that his software is active to use it. He just wants to read the vehicle, fix it, and move on to the next task,” Kraemer concluded.  

Tech to the Rescue

There are numerous tools to help with vehicle diagnostics. A few options include code readers, scan tools, and diagnostic solutions provided by the automakers directly.

“Code readers and scan tools are must-have assets in a shop today. Being able to hook up to a vehicle and pull pertinent information from that vehicle is an important step in reaching a resolution. A scan tool will tell you what component parameters are out of range.

"Still, technicians also need a repair information resource such as TruckSeries from Mitchell 1 to access the proper repair procedures, diagrams, and specifications. Access to this information, along with their experience and expertise, is what will get that truck back into operation,” said Kristy LaPage, business manager, Commercial Vehicle Group for Mitchell 1.

Tom Kraemer, account manager for Snap-on Business Solutions/NEXIQ Technologies, also noted the value of a scan tool. 

“Having a scan tool, or diagnostic tool, that properly reads the vehicle and the related systems on the vehicle is extremely important. The technician needs to read the vehicle’s overall health to make sure that everything is interacting properly.

"If the technician is reading the engine, they will not be aware of another module causing the engine to go into de-rate. The after-treatment system is a perfect example; it has its own set of modules and can control the engine’s overall performance. Every module on the vehicle interacts with all the others,” Kraemer said.

If a fleet has telematics capabilities, Connected Diagnostics and/or Connected Advisor from Cummins can help improve diagnostic-related issues by sending notifications of vehicle fault codes to the owner-operators or fleet managers. 

“Connected Advisor can provide recommended actions and inform the fleet managers of critical items that need to be addressed. Free tools like Cummins PowerSpec can read and reset fault codes outside of telematics when connected to an engine.

"For further detail, Cummins INSITE, Guidanz, EDS, and QuickServe Online can provide troubleshooting steps, service recommendations, and more vehicle information,” said Aparna Venkatraman, director of digital product management for Cummins Inc.

Mack’s medium-duty MD Series is supported through Geotab Go, offering access to Mack OneCall agents, available 24/7 at the Mack Uptime Center based in Greensboro, N.C. 

“In addition to access to Mack OneCall agents, we connect with MD Series owners through Mack ASIST, our online communications and service management portal. This platform gives the vehicle’s decision-maker, Mack OneCall agents, and the nearest dealer one consistent location for all case information in real time. The factory-installed Geotab Go telematics device integrates Mack’s engine and transmission partners for the MD Series,” said David Pardue, Mack Trucks vice president of connected vehicle and contract services.

Kenworth also offers TruckTech+, helping fleets monitor their trucks on the road. 

“Minor issues can be addressed on the road or back at the home terminal, while larger issues can be diagnosed and fixed at the nearest Kenworth dealership. Notifications to customers, via email, may include keep driving, no action required; keep driving and have the fault addressed during the next service interval; head to a dealer for service; or pull over to prevent damage.

"If the customer needs to take the truck in for service, the system maps out the locations of the three closest repair facilities. In addition, the data is sent to a secure web portal where the fleet manager can review the truck’s location, status, identified issue, and recommended solution,” noted Jeff Parietti, Kenworth public relations manager. 


About the author
Lauren Fletcher

Lauren Fletcher

Executive Editor - Fleet, Trucking & Transportation

Lauren Fletcher is Executive Editor for the Fleet, Trucking & Transportation Group. She has covered the truck fleet industry since 2006. Her bright personality helps lead the team's content strategy and focuses on growth, education, and motivation.

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