Fleet Maintenance - 34

DIAGNOSTICS
»Fleets can benefit from a fully
functional diagnostic tool that can help
solve a range of DPF-related problems,
including forced regens, system resets,
and a variety of DEF system tests.
Image courtesy of Cojali USA

How aftermarket
diagnostic tools can assist
with DPF maintenance

Fleets can mitigate DPF-related issues when a diagnostic
tool can handle everything from regens and resets to the
pinpointing of hidden problems throughout the system.
By Gregg Wartgow
CONTRIBUTING EDITOR

Proper management of a truck's diesel
particulate filter (DPF) system requires an
understanding of how the truck's specific
system works as well as what maintenance
is needed and when. In the event that something goes awry, it's also nice to have a fully
functional diagnostic tool that can help solve
a range of problems.
"The DPF has always been the bane of my
existence," says Chris Freeman, director of sales/
training HD at Autel, a developer of intelligent
diagnostics, detection, and analysis systems. "I
can honestly say that 90 percent of the problems
trucks see these days are DPF-related."
A common issue modern trucks face is the
DPF becoming clogged.
"The DPF will not work properly if it
gets clogged, and then the aftertreatment system will cause power
»Cojali's Jaltest CV Kit is designed
to be an all make and model
diagnostic solution for fleets. Its
functionality includes
bidirectional controls,
including DPF regens.
Image courtesy of Cojali USA

34 Fleet Maintenance | July 2020

issues," says Bruno Gattamorta, vice president
of sales and marketing for Cojali USA, a manufacturer of technology and diagnostic tools.
"There are five stages of aftertreatment issues,
ranging from a lax warning light to the vehicle
being placed into limp mode."
To prevent an issue from escalating, regimented preventive maintenance is key.
"Regular maintenance is important to
remove ash that builds up within the DPF

before it becomes clogged, which can create
high back pressure and more frequent regenerations," says Bruce Balfour of Clean Diesel
Specialists Inc. (CDS), an integrated data-logging, installation, retrofitting, cleaning, parts
distribution, and compliance center. CDS is a
longtime Cojali customer.
As Autel's Freeman explains, a DPF system
uses a series of regenerations (regens) to burn
off ash. But if the system's sensor says there
is too much NOx in the system, it will force
diesel exhaust fluid (DEF) into the system to
help burn off the NOx. Sensors and DEF make
what sounded like simple filter maintenance
much more complex.
Freeman says another challenge for technicians is a lack of standardization in the
industry. Some DPF systems, for example,
include selective catalytic reduction (SCR)
while others do not. Some have SCR but lack
a DPF. Some systems have sensors on the DPF,
but not on the SCR, or vice versa. Technicians
often require a good all-makes diagnostic tool
that will help them stay on top of this wide
range of potential DPF-related issues.

What core functionality should
a diagnostic tool have?

First and foremost, fleets need a diagnostic
tool that is capable of executing the necessary
DPF cleaning procedures. Fleets can't always
count on running regens. Forced (manual)
regens often become necessary.
"Some fleets have to set up a schedule for
performing manual regens, whether that is
once a week or whatever," Freeman says.
»As part of its latest update, Cojali's
Jaltest diagnostic software has a new
system display that shows gauges in real
time, allowing measurements to be read
while an action is being carried out.
Image courtesy of Cojali USA

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