Fleet Maintenance - 35

DIAGNOSTICS
AUTOMOTIVE INTELLIGENCE
ute process most of the time. But if
you don't have the functionality on
your scan tool, that could turn into
a very expensive three-day process
where you may even need to call in
help from a dealer."

Beyond the filter

Filter maintenance represents just
one step in the DPF system. In some
instances, solving a DPF-related
problem involves pinpointing
where the problem originated in
the first place. That is why Freeman
says it's important to consider the
entire DPF system when seeking
out diagnostic tool functionality.
»Many DPF-related issues tie back to DEF performance.
For example, a tool should be
A good diagnostic tool will help technicians run a series of
able to address DEF performance.
tests to help pinpoint issues within the DEF system.
"You want to be able to conduct a
Image courtesy of Autel
variety of tests including DEF pump
tests, purge tests, DEF injector tests,
tank heater tests, pipe heater tests,
and others," Freeman explains.
"A lot of times, DPF system issues
trace back to the DEF," Freeman
continues. "I had a customer who
wasn't getting any DEF into the
exhaust. After testing, we'd identified a problem with the DEF doser
block. The customer originally
thought it was an injector problem.
»A good diagnostic tool will help technicians analyze "cascading
We ran a test and ruled that out.
codes" so they can pinpoint the root causes of DPF-related issues.
The faulty doser valve needed to be
A unique feature of Autel's tool is freeze-frame data, which
replaced ... which wasn't great news,
captures ECM data at the precise moment a fault code occurred.
but we pinpointed the problem in
Image courtesy of Autel
a short amount of time which was
A good example is a fleet running city routes
most important."
where vehicles rarely get up to the necessary exhaust
Another fleet using an Autel diagnostic tool had an
temperature for a running regen to kick in.
issue with an engine going into air-intake derate mode
For fleets looking to do a fair amount of forced regens,
when the vehicle was driven above 50 percent throttle.
an all-makes aftermarket diagnostic tool makes sense.
The technician discovered similar pressure levels on
For example, Cojali's Jaltest, an all-makes diagnostics
both sides of the turbocharger, which is odd because
tool, allows a technician to launch a forced regen, reset
there should never be as much pressure on the exhaust
the filter, and monitor all of the relevant measurements
side. On this particular truck, there were monitoring
to ensure that the process is working adequately.
sensors on the DPF, but not the SCR. The DPF itself had
In addition to forced regens, CDS' Balfour says
imploded, sending debris in the DPF housing and SCR.
any good diagnostic tool should do the following:
That congestion caused additional pressure to build
Ü Scan, read, and clear codes of the aftertreatment
up and begin bleeding over to the exhaust side of the
module and engine control module
turbo. Because there were no sensors on the SCR, the
Ü Conduct hydrocarbon 7th injector and DEF injecECM could not detect this problem.
tor testing
"The technician was able to use our diagnostic
Ü Run all tests for OE-specific aftertreatment systems
tool to check pressure levels on both sides of the
(i.e. SCR efficiency, DOC efficiency, DPF efficiency,
turbo," Freeman says. "The technician was also able
NOx sensor)
to connect a four-channel scope to the tool and read
Ü Reset the ash counter, maintenance intervals, and
signals going into each of the sensors to verify the
filter replacement serial number coding
data. Essentially, this helped the technician avoid
Fixing the DPF via a regen is not always the solution.
needlessly changing out a sensor, which would have
Sometimes the filter needs to be taken out of the truck
cost money but not solved the problem."
and cleaned in order to remove an adequate amount
In the case above, no fault codes were triggered;
of ash. Other times, the filter needs to be replaced. In
the vehicle was just sent into derate mode. In most
DPF-related instances, however, a fault code is trigeither event, there must be a communication to the
ECM that everything is ready to go with the DPF. This is
gered. In fact, several codes are sometimes triggered.
the DPF reset function which Balfour referenced above.
A good diagnostic tool will help technicians analyze
"A lot of aftermarket diagnostic tools do not have
these "cascading codes" so they can determine how
this reset functionality," Autel's Freeman points out.
they are related, which occurred first, and how to go
"When shopping for software, make sure it will be able
about pinpointing the actual problem that needs to
to perform these reset functions. It's literally a five-minbe resolved.

ENHANCED
SOFTWARE

NEW BI-DIRECTIONAL
CONTROLS

MORE THAN 1,000 NEW DIAGNOSTIC UPDATES
OVER 20 MAKES / 80+ MODELS

ALL MAKES / ALL MODELS
CLASS 1 (0-6,000LBS) - CLASS 9 (33,000LBS)

EASY INTERFACE / TROUBLE CODE ASSIST / DETAILED AUTO-SCAN

MAXIMIZE

TECHNICIAN RESOURCES
2019 MODELS / ADAS, TPMS & TRAILER SYSTEMS
FREIGHTLINER, KENWORTH, PETERBILT & INTERNATIONAL
VehicleServicePros.com/10095724

TEL: (855) 288-3587 * USSUPPORT@AUTEL.COM
AUTEL.COM * MAXITPMS.COM * MAXISYSADAS.COM

http://www.AUTEL.COM http://www.VehicleServicePros.com/10095724 http://www.MAXITPMS.COM http://www.MAXISYSADAS.COM

Fleet Maintenance

Table of Contents for the Digital Edition of Fleet Maintenance