Heavy Duty: Keeping Up With Modern ABS

What your technicians need to know about troubleshooting today’s ABS.

“(Technicians need to know) not only those specifics, but how the systems work as a whole—theoretically speaking, how the ABS monitors wheel speed, how it’s looking at wheel speed and how it reacts during certain vehicle maneuvers is also a key that a lot of technicians really need to know when they’re working on a system,” he says.”

The basics are still just as important though—when installing or removing the systems, Williams says technicians should make sure they stick to proper procedures.

“Be careful where they tie-strap a connector or a wiring harness,” he says. “That is very important.”

Bendix’s Conklin says their system will announce the need for maintenance, giving technicians one less thing to worry about.

“Of course, a driver with good pre-trip inspections and periodic vehicle inspections is always a good practice, but the system keeps pretty good tabs on its relative health and the diagnostic tools available make it fairly simple to diagnose and service,” he says. “We don’t get a lot of calls we don’t understand, because the tools have reached a maturity and also the technicians have reached a maturity where they’ve got it.”

Good preventative maintenance practices are still important, though.

“These don’t take away the responsibility for keeping an eye on things and keeping things in adjustment and checking things out ahead of time,” Andersky says.

Stocksdale says most ABS problems are related to the power source or wheel speed sensor.

“Anytime you’re maintaining the wheel end or an initial installation, make sure you have a good, solid installation; the sensor pushed up against the exciter ring and again, dialectic grease at any connecting point,” he says.


Today’s ABS can help keep your trucks moving safely down the road, and fleets have plenty of good options to meet their needs, but ultimately how well they work depends on you and your technicians.

While modern electronics have certainly made it less time-consuming to properly maintain anti-lock braking systems, it takes no less dedication to making sure none of your technicians takes a shortcut in the shop that could lead to disaster on the highway.

The trick is getting your technicians to buy into the fact that while checking the brakes might now take a lot less of their workday, they can’t give it short shrift.

Do that, and ABS will help keep your fleet safely and efficiently moving forward.


Bob Blair, CEO of Lite-Check said the company’s “910B” inspector is a necessary tool for technicians that maintain ABS.

Blair says the advantage of their tool is that it can test a vehicle’s air, brake and electrical systems, which are all connected to ABS.

“So on the electrical (side), for example, if the software in the tester discovers a circuit fault it will automatically sound an alarm and tell you what the fault is,” Blair says. “So the technician can be at the rear of the trailer, 50-70 feet away from the tester, press a button like a brake circuit, and he hears the alarm and he can see that the lights are not operating correctly and now he knows he’s got a problem. The moment he corrects that, the alarm (shuts) off.”

The goal, Blair says, is reducing the time needed for technicians to diagnose ABS problems, leaving them more time to make repairs.

“TMC conducted a survey and determined than 30-35 percent of a technician’s time was spent diagnosing, not fixing, so we’ve approached it from the standpoint, ‘Can we get that information to the technician within a second?’” he says. “And now you’re getting a good population of vehicles out there with ABS on it, and (fleet officials) are also starting to realize the time required to diagnose the problems. (Also), when the technician is on the service truck, he now only needs this one tool and when he connects with the seven-way (plug), he can read ABS and electrical at the same time.”

Well-maintained fleet vehicles’ ABS should be checked after every major cross-country run or every 30 days, Blair says, so being able to make a quick check is important.

“The advantages of not having road costs and violations and all that kind of things are incredible,” he says. “When the tester can identify what the problem is with that sensor within a fraction of a second, how much help is that for the person working in the rain?”

The tester comes with manual and a “cheat sheet,” but Blair says they are rarely needed.

“We rarely get a call on how to use it,” he says. “You connect the seven-way and the two airlines, press the ABS key and it will automatically search and identify which type of system is on the trailer and automatically pull up the first fault on the screen. If the technician is not familiar with that fault, he hits another button and it will scroll through a help process—‘Check this, measure this,’ whatever, so he doesn’t need a manual.”

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