User guide

AutoEnginuity ScanTool User Guide 57
Oxygen Sensor Heater Monitor
This non-continuous monitor evaluates the working state of all
oxygen sensor heaters in the vehicle. A vehicle will operate in an
open loop until the oxygen sensors are up to operating temperature.
It will use the default parameters stored in the engine computer to
regulate fuel trim. When an oxygen sensor heats up to around 600
º
F the engine computer switches to a closed loop and uses the values
from the oxygen sensor to influence the fuel trim. To allow for a
quick transition between the open and closed loop state, oxygen
sensors are heated. This is a "Two-Trip" monitor. See also Oxygen
Sensor.
Oxygen Sensor Monitor
This monitor evaluates the working state of all oxygen sensors in
the vehicle. It monitors the minimum and maximum voltage levels,
switching frequency (crosscounts), the response rate of each oxy-
gen sensor, etc. The testing threshold and ranges can be exported to
the ScanTool and viewed in the Oxygen Sensor Test Results area of
the O2 Sensor window. This is a "Two-Trip" monitor. See also Oxy-
gen Sensor.
PCM or Powertrain Control Module
The onboard computer controlling the engine systems. Some
vehicles may have electronic transmission functions as part of the
PCM responsibilities.
PID or Parameter Identification
An OBD-II standard term for a sensor and its respective functional-
ity.
Secondary Air System
This system is used to assist the catalytic converter in burning off
emissions related gases. When a cold engine is started, several
components necessary for emissions regulation will not be up to
operating temperature. The engine computer operates in an open
loop. In this case, the catalytic converter has oxygen forced into the
exhaust stream by way of a of the secondary air system to assist in
burning off all of the unburned or partially burned fuel. The second-
ary benefit of the oxygen being injected into the catalytic converter