System Status And Drive Cycle For Satisfying Federal Inspection/Maintenance (I/M 240) Regulations; Common Obd Ii Terms - Isuzu 1999 RODEO Workshop Manual

6E1–30
RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
Output Components:
Output components are diagnosed for proper response to
control module commands.
functional monitoring is not feasible will be monitored for
circuit continuity and out–of–range values if applicable.
Output components to be monitored include, but are not
limited to the following circuit:
f Idle Air Control (IAC) Motor
f EVAP Canister Purge Valve Solenoid
f A/C relays
f Cooling fan relay(s)
f VSS output
f MIL control
f Cruise control inhibit
Refer to PCM and Sensors in General Descriptions.
Passive and Active Diagnostic Tests
A passive test is a diagnostic test which simply monitors a
vehicle system or component. Conversely, an active test,
actually takes some sort of action when performing
diagnostic functions, often in response to a failed passive
test. For example, the EGR diagnostic active test will
force the EGR valve open during closed throttle decel
and/or force the EGR valve closed during a steady state.
Either action should result in a change in manifold
pressure.
Intrusive Diagnostic Tests
This is any on–board test run by the Diagnostic
Management System which may have an effect on
vehicle performance or emission levels.
Warm–Up Cycle
A warm–up cycle means that engine at temperature must
reach a minimum of 70°C (160°F) and rise at least 22°C
(40°F) over the course of a trip.
Freeze Frame
Freeze Frame is an element of the Diagnostic
Management System which stores various vehicle
information at the moment an emissions–related fault is
stored in memory and when the MIL is commanded on.
These data can help to identify the cause of a fault. Refer
to Storing And Erasing Freeze Fame Data for more
detailed information.
Failure Records
Failure Records data is an enhancement of the OBD II
Freeze Frame feature. Failure Records store the same
vehicle information as does Freeze Frame, but it will store
that information for any fault which is stored in on–board
memory, while Freeze Frame stores information only for
emission–related faults that command the MIL ON.
Components where
System Status And Drive Cycle For
Satisfying Federal
Inspection/Maintenance (I/M 240)
Regulations
I/M Ready Status means a signal or flag for each
emission system test that had been set in the PCM. I/M
Ready Status indicates that the vehicle on–board
emissions diagnostics have been run. I/M Ready Status
is not concerned whether the emission system passed or
failed the test, only that on–board diagnosis is complete.
Not all vehicles use all possible I/M flags.

Common OBD II Terms

Diagnostic
When used as a noun, the word diagnostic refers to any
on–board test run by
Management System. A diagnostic is simply a test run on
a system or component to determine if the system or
component is operating according to specification. There
are many diagnostics, shown in the following list:
f Misfire
f Oxygen sensors
f Oxygen sensor heaters
f EGR
f Catalyst monitoring
Enable Criteria
The term "enable criteria" is engineering language for the
conditions necessary for a given diagnostic test to run.
Each diagnostic has a specific list of conditions which
must be met before the diagnostic will run. "Enable
criteria" is another way of saying "conditions required".
The enable criteria for each diagnostic is listed on the first
page of the DTC description in Section 6E1 under the
heading "Conditions for Setting the DTC". Enable criteria
varies with each diagnostic, and typically includes, but is
not limited to the following items:
f engine speed
f vehicle speed
f ECT
f MAP
f barometric pressure
f IAT
f TP
f high canister purge
f fuel trim
f A/C ON
the vehicle's Diagnostic