Description: Second-generation onboard
diagnostics, more commonly known as OBDII, is a sophisticated
onboard computer system that was first used on some 1994 and 1995
model vehicles. Since 1996, it is used on all makes and models and
cars and light trucks. OBDII uses a network of sensors to monitor
operating conditions.
Purpose:
The
Environmental Protection Agency mandated the application of OBDII technology in
order to keep tighter reins on vehicle emissions. In
addition, OBDII brings about certain standards intended to help streamline
the diagnostic process, regardless of the make of vehicle. The system
also alerts you with a Malfunction Indicator Lamp
(MIL), indicating that the system has detected
a problem, which could cause excessive emissions. This
light is usually labeled SERVICE ENGINE SOON or CHECK ENGINE. If the light
appears, you should have its cause investigated by a
professional technician at your earliest opportunity. If the light flashes, the condition is more severe and must be checked out immediately to prevent damage to the catalytic converter.
Maintenance Tips/Suggestions: Perform routine maintenance as
recommended in your owner’s manual. The onboard computer, otherwise
know as the powertrain control module, stores a Diagnostic Trouble
Code (DTC) when it detects a problem in one of the monitored
circuits. A professional technician can access this information
using a scan tool connected to
the vehicle’s Data Link Connector
(DLC). Although many DTCs are sensor-related, it does not necessarily indicate
a faulty sensor. There may be problems in that sensor’s circuit,
or there may be several interrelated problems. Areas of the country
with an emissions testing program are placing
added value on OBDII checks, where this technology may be
used in place of tailpipe testing.
