User guide

AutoEnginuity ScanTool User Guide 33
General Systems
The General Systems in the upper-right of the window shows
the fuel system, the secondary air, the power-on takeoff status, and
battery voltage. These system values are typically used to deter-
mine whether an IM monitor test can begin or complete.
The Fuel System Status is used to determine if the O2 sensors
are being used in the fuel loop. An engine typically won’t enter into
a Closed Loop until after 20 to 30 seconds. Common reporting con-
ditions are:
Closed:
Closed (With O2 Fault):
Fuel trim is being influenced by O2 sensor readings.
Open:
Fuel trim is coming from the hard-coded settings in the
ECM usually because the system isn’t up to operating tempera-
ture.
OBD-II IM-based Emissions Testing
An OBD-IM check consists of two types of examinations: A
visual check of the dashboard display function and status (also
known as the MIL and/or bulb check), and an electronic exami-
nation of the OBD computer itself.
1. Visually examine the instrument panel to determine if the
MIL illuminates briefly when the ignition key is turned to the
"key on, engine off" (KOEO) position.
2. Locate the vehicle’s data link connector (DLC) and plug a
scan tool into the connector.
3. Start the vehicle’s engine so that the vehicle is in the "key
on, engine running" (KOER) condition. The MIL may illumi-
nate and then extinguish during this phase. Continued illu-
mination while the engine is running is cause for failure.
4. Check the vehicle’s IM readiness states. (What constitutes
failure is non-uniform; however, typically two IM monitors
Not Completing is a failure. Some states won’t allow any to
be Not Complete.)