Fleet Maintenance - 23
»»Communication protocols not only
allow for standardized communication
between vehicle systems, they also provide
standardized information about the
vehicle's performance and diagnostics.
Photo courtesy of Noregon
standardizing communication between systems.
Additionally, challenges with how vehicle systems
communicate can have a significant impact on the
maintenance and service of a commercial vehicle.
Overview of standardized
A vehicle bus is the term used for a communication network, or channel, which allows electronic control units (ECUs) on different systems of a
vehicle to send and receive data and messages to
and from one another. The transfer of data on a
vehicle bus can be done without requiring a host
computer, or excessive wiring, to connect to the
different vehicle systems.
Bruno Gattamorta, vice president, diagnostic
sales for heavy duty scan tool manufacturer
Cojali USA, provides an example of how data
messages are transferred between the differ-
ent ECUs, or what he refers to as "nodes," on a
"Messages are transmitted or broadcast through
a node structure - a sort of highway - where any
node can have access to any other node in the
network," he explains. "This makes communication much faster as it doesn't require a sequential
decoding as in the past, but all channel data at
the same time."
ECUs collect data readings through sensors and
actuators and manage the operation of various
systems on a vehicle. Two common ECUs are the
powertrain control module (PCM), which manages
communication for systems like the engine and
aftertreatment systems, transmission, brakes,
and ADAS; and the chassis control module (CCM)
which includes systems such as body control
units, instrument clusters, restraint systems, and
TPMS. A commercial vehicle can have dozens of
ECUs to manage different systems. Data transfer
between these ECUs is made possible through
standardized communication protocols.
"A standardized communication protocol
creates a common language that allows for proper
communication between various subsystems on
a vehicle," says Dave Covington, CTO, Noregon.
"When using a standardized protocol, components
are able to share data, and command and control
each other's actions."
Noregon offers products that assist with the
diagnosis and repair of vehicles and assist in total
vehicle health and safety management.
Standards are released through the U.S.-based
Society of Automotive Engineers (SAE), the
International Organization for Standardization
(ISO), and the American Truck Associations'
Technology & Maintenance Council.
Bosch introduced a standardized specification
for a vehicle bus in the 1980s, referred to as the
communication area network, or CAN bus.
The CAN bus was originally released as an
SAE standard, with subsequent ISO standards
announced a few years later. Several updates
have been made to the original CAN bus specification, to remain flexible to the changes in
Modern vehicles today have several vehicle bus
communication networks to ensure the transfer of
ever-increasing data between micro-control units.
"It is not uncommon to see a vehicle with two
or three communication networks, and more than
one communication protocol in use," explains
Brian Herron, President, Drew Technologies.
"There is a significant amount of data being
transmitted on the vehicle's network, including
driving information, fault codes, and information
collected from sensors for each system. This data
can be used not only for maintenance, but also to
capture analytics on the operation of the vehicle."
A division of Opus IVS, Drew Technologies
manufactures diagnostic and reprogramming
products for the automotive and commercial
Vehicles have a primary, or "gateway" ECU
that receives information from all the different systems and makes them "talk the same
language," explains Fabio Mazzon, technical
manager for TEXA USA. "If the ABS talks on a
J1708 [communication standard] while the engine
uses a J1939 standard, the gateway shares infor-
»»The IOSiX ELD Connector, to the left of the clutch petal, is
plugged into a Deutsch 9-pin port on a Freightliner Cascadia.
This device is used to monitor hours of service, analyze fuel
consumption and driver behavior, and perform diagnostics. The
device will soon be able to perform forced DPF regeneration,
and temporarily suspend emissions-related engine derating.
Photo courtesy of IoSiX
»»The black Type-I 9-pin adapter (left) is limited to a 250 kbps
data transfer rate and designed for vehicles manufactured before
2016, while the green Type-II 9-pin adapter provides up to a 500
kbps data transfer rate and works on 2016 and newer vehicles.
Photo courtesy of IoSiX
mation between the two and makes them work
TEXA provides products to assist with truck
diagnostics, including the recent release of its
aftermarket remote diagnostics device.
There are a variety of vehicle communication
protocol types in use on today's vehicles, which
communicate on a vehicle bus. A majority of
on-road vehicles follow two main communication
standards: OBD-II (defined by J1962 and J1979
SAE protocols) for light duty passenger vehicles
and J1939 for heavy duty commercial vehicles.
Some heavy duty vehicles may also follow J1708,
or Heavy Duty (HD) OBD communication standards. Medium duty vehicles are even more challenging to define and can follow any number of
protocols listed above.
OBD-II started as a standardization to monitor
vehicle emissions. It is required on all 1996 and
newer model passenger vehicles. A 16-pin adapter
is used to access an OBD-II diagnostic port on a
vehicle. Heavy duty OBD, or HD OBD, is a standard for heavy duty vehicles that share similarities with OBD-II. It has been in development and
implemented by a number of truck manufacturers
that have passenger vehicle counterparts.
For example, Mack Trucks and Volvo recently switched to HD OBD. And, Hino Trucks uses
HD OBD for their medium duty trucks. More
widespread adoption of HD OBD will continue,
"HD OBD is being adopted at a wide rate in
[the U.S.] because of its success in European
countries," Covington explains. "Manufacturers
who sell a high percentage of their components
in Europe are looking to ... synchronize their
platform and release the same components in
America without large-scale adjustments to the
May 2019 | VehicleServicePros.com
Table of Contents for the Digital Edition of Fleet Maintenance
Uptime - Are You Communicating with Employees Effectively?
Trends in Heavy Duty Diesel Engine Oils
Vehicles - Keys to Consistent Liftgate Performance
In the Bay - How Standardized Vehicle Communication Protocols Impact Diagnostics and Vehicle Operation
Shop Operations - Considerations for Mobile Device Usage in the Shop
Training - Where are all the Students Going?
Management - Why the Recent Airline Accidents Should be Concerning
Fleet Parts & Components
Tools & Equipment
Guest Editorial - How Much Do You Spend on DPF Maintenance?
Fleet Maintenance - 1
Fleet Maintenance - 2
Fleet Maintenance - 3
Fleet Maintenance - 4
Fleet Maintenance - 5
Fleet Maintenance - 6
Fleet Maintenance - 7
Fleet Maintenance - Uptime - Are You Communicating with Employees Effectively?
Fleet Maintenance - 9
Fleet Maintenance - Trends in Heavy Duty Diesel Engine Oils
Fleet Maintenance - 11
Fleet Maintenance - 12
Fleet Maintenance - 13
Fleet Maintenance - 14
Fleet Maintenance - 15
Fleet Maintenance - 16
Fleet Maintenance - 17
Fleet Maintenance - Vehicles - Keys to Consistent Liftgate Performance
Fleet Maintenance - 19
Fleet Maintenance - 20
Fleet Maintenance - 21
Fleet Maintenance - In the Bay - How Standardized Vehicle Communication Protocols Impact Diagnostics and Vehicle Operation
Fleet Maintenance - 23
Fleet Maintenance - 24
Fleet Maintenance - 25
Fleet Maintenance - 26
Fleet Maintenance - 27
Fleet Maintenance - Shop Operations - Considerations for Mobile Device Usage in the Shop
Fleet Maintenance - 29
Fleet Maintenance - 30
Fleet Maintenance - 31
Fleet Maintenance - 32
Fleet Maintenance - 33
Fleet Maintenance - Training - Where are all the Students Going?
Fleet Maintenance - 35
Fleet Maintenance - Management - Why the Recent Airline Accidents Should be Concerning
Fleet Maintenance - Fleet Parts & Components
Fleet Maintenance - 38
Fleet Maintenance - 39
Fleet Maintenance - 40
Fleet Maintenance - Tools & Equipment
Fleet Maintenance - 42
Fleet Maintenance - 43
Fleet Maintenance - 44
Fleet Maintenance - Classifieds
Fleet Maintenance - Guest Editorial - How Much Do You Spend on DPF Maintenance?
Fleet Maintenance - 47
Fleet Maintenance - 48