Equus 3123 - GM Code Reader (1982 - 1995) - Manual (Page 45)

Glossary
GM 4-6
HPA - High Pressure Accumulator.
IAC – Idle Air Control.
IAS – Inlet Air Solenoid valve or its circuit.
IAT – Intake air temperature sensor, performs same function
as MAT sensor.
ICM – Integrated Control Module.
IDLE TRACKING SWITCH – An input device that sends a
signal to the computer to indicate a closed throttle condition.
IGN – Ignition.
INTERMITTENT FAULT – Fault which occurred during a
previous engine operating cycle. Intermittent fault may have
set a fault code which is still present in PCM memory.
ISA – Idle Speed Actuator. Extends or retracts to control
engine idle speed and to set throttle stop angle during
deceleration.
ISC – Idle Speed Control, either computer control motor, air
bypass valve, or any device used to control idle rpm.
ISO VALVE - Isolation Valve.
ITS – Idle Tracking Switch.
KAM – Keep Alive Memory. Battery power memory locations
in computer used to store failure codes and some diagnostic
parameters.
KAPWR – Keep Alive Power, used to power KAM circuit of
the processor.
KNOCK SENSOR (KS) – Input device that responds to spark
knock, caused by over advanced ignition timing.
LEAN MIXTURE – Air/fuel mixture that has excessive
oxygen left after all fuel in combustion chamber has burned, 1
part fuel to 15 or more parts air.
LED – Light Emitting Diode.
LOCK UP TORQUE CONVERTER – Converter with
internal mechanism that locks turbine to impeller when
engaged.
LPA - Low Pressure Accumulator.
LUS – Lock-Up Solenoid.
M/C – Mixture control or mixture control solenoid.
MAF – Mass Air Flow sensor, used to measure amount of
airflow through the throttle body.
MAP – Manifold Absolute Pressure sensor or its circuit.
MAT – Manifold Air Temperature.