Equus 3145 - Digital Ford Code Reader (1981 - 1995) - Manual (Page 87)

Glossary
GLOSSARY OF TERMS AND ABBRREVIATIONS
Chapter 6 84
OHC – Overhead Cam
OXYGEN SENSOR – Sensor that changes its voltage output
as exhaust gas oxygen content changes as compared to the
oxygen content of the atmosphere. The constantly changing
electrical signal is used to control fuel mixture.
PCM – Powertrain Control Module. Computer that controls
engine fuel, ignition and emission related functions.
PCV – Positive Crankcase Ventilation. System that controls
flow of crankshaft vapors into engine intake manifold where
they are burned in combustion rather then being discharged
into the atmosphere.
PFE – Pressure Feedback EGR sensor or its circuit.
PFI – Port Fuel Injection.
PIP – Profile Ignition Pickup.
PORTED VACUUM SWITCH – Temperature actuated
switch that changes vacuum connections when the coolant
temperature changes.
POT – Potentiometer.
POWERTRAIN CONTROL MODULE – Same as ECM, but
also controls electronically controlled automatic transmission.
PROFILE IGNITION PICKUP – A Hall effect vane switch
that furnishes crankshaft position data to the EEC-IV
processor.
PROM – Programmable Read Only Memory.
PSPS – Power Steering Pressure Switch. Signal is used by
computer to compensate for power steering loads.
PVS – Ported Vacuum Switch.
QUICK TEST – A functional diagnostic test for Ford EEC-IV
system, consisting of test hookup, key on engine off, engine
running and continuous self test models.
RAP – Retained Accessory Power.
RELAY – Switching device operated by a low current circuit,
which controls opening and closing of another higher current
circuit.
RELIEF VALVE – Pressure limiting valve located in exhaust
chamber of thermactor air pump. Relieves part of exhaust
airflow if pressure exceeds a calibrated value.
RICH MIXTURE – Air/fuel mixture that has more fuel than
can burn completely, 1 part fuel to 14 or less parts air.
SAW – Spark Advance Word, and also Spark Angle Word.
SC – Super Charged
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