OBDII WHAT IS IT? OBDII refers to On Board Diagnostics
generation two. This is a system that has the ability to test
it's various components and systems and tell the driver when a
fault has been detected that will cause their vehicle to put out
excessive emissions. This system first became available on
passenger cars in the 1995 model year and 1996 for light trucks
with a gross vehicle weight of under 8500lbs. WHAT CAN THE
SYSTEM DETECT? The system has the ability to detect malfunctions
in many engine systems that can cause excessive emissions. Let's
look at the individual system checks or monitors and how they
work. OXYGEN SENSOR SYSTEM MONITOR The 02 sensors are monitored
or checked for proper reference signals and to make sure that
the heater circuit is functioning. 02 sensors that are located
before the catalytic converter are tested for high and low
voltage thresholds and for switching frequency. The switching
frequency test will count the number of times that the signal
voltage goes beyond the mid point