Onboard diagnostics have come a long way since they were first introduced in the 1980s. Their initial purpose was to alert
drivers when vehicles experienced specific service problems that could prevent them from meeting federal emissions standards
so that those problems could be promptly addressed. That's still a key goal of today's federal onboard diagnostic (OBD) mandates,
but automakers also have leveraged the same technology to support a host of additional service alerts. Some are even adding
the ability to transmit diagnostic data over the cellular network to service technicians.
Over the years, the functions that can be diagnosed have expanded tremendously, said Mark Schaefer, director of marketing
for tool manufacturer Snap-on Diagnostics, one of several independent tool makers that work in cooperation with automakers
to deliver tools that can work with vehicles from multiple manufacturers. "In the past, each car may have had one or a few
computers," says Schaefer. "Now you have 20 on a basic car and 70 on some models." To support new functionality, diagnostic
tools regularly require new software updates — and may even need a memory upgrade.
A system from Hughes Telematics will include two-way cellular communications that connects directly to the cars computer
bus. (ILLUSTRATION COURTESY: HUGHES TELEMATICS)
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An important change beginning with the 2008 model year is a requirement for all manufacturers to support the controller area
network (CAN) standard, which links various computers on a vehicle. Manufacturers are required to use CAN for emissions-related
diagnostics but may continue to use a range of protocols in diagnosing non-emissions-related problems. Some scan tools may
need an adapter, as well as software downloads, to support the new requirements, according to David Rich, product manager
of Equus Products, an independent tool manufacturer.
Another new function that will be required on 2010 model year vehicles has already begun to show up on some current production
models. That diagnostic adds a fourth system status, known as "permanent" to the previous three — pending, current and history.
The goal is to further enhance the diagnostic system's ability to prevent vehicles that do not fully meet emissions requirements
from passing inspections, said Andrew Mutter, service technician supervisor for Toyota. When the diagnostic system detects
an emissions-related problem, a permanent code is set. Depending on the problem, a technician may have to test drive the vehicle
to clear the code. Some Toyotas, beginning with the 2008 model year, already support "permanent" status functionality, Mutter
said.
Chrysler also continues to expand its diagnostic functions, said Nick Cappa, a company spokesman. "We have created tools tailor-made
for hybrid systems to monitor an entirely new set of sensors and systems operation," he says. "As Chrysler begins to develop
electric vehicles, the data will again shift."
The potential of wireless diagnostic systems to gather information without the vehicle owners consent concerns some industry
stakeholders. (PHOTO COURTESY: SNAP ON)
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The biggest change involving onboard diagnostics is increased use of wireless communications. General Motors' OnStar system,
originally designed to enhance roadside and emergency assistance through a cellular link, offers monthly diagnostic reports
to owners via e-mail. Recently, the company took that capability a step further by offering customers the option of having
alerts also sent to the General Motors dealer of their choice. Owners also can initiate diagnostic tests and send them to
the dealer as needed if they have a problem or want to prepare for a long trip.
