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Engine Oil Pressure (Switch)
EOT
Engine Oil Temperature (Sensor)
EPA:
Environmental Protection Agency.
ESC:
Electronic Spark Control. An ignition system function that warns the PCM when knock is detected. The PCM then retards spark timing to eliminate the knocking condition.
EST:
Electronic Spark Timing. An ignition system that allows the PCM to control spark advance timing. The PCM determines optimum spark timing from sensor information — engine speed, throttle position, coolant temperature, engine load, vehicle speed, Park/Neutral switch position, and knock sensor condition.
EVAP:
Evaporative Emissions System.
FC:
Fan Control
Freeze Frame:
A block of memory containing DTCs of the vehicle operating conditions for a specific time.
FTP:
Federal Test Procedure. Strict test of vehicle’s emissions.
Fuel Trim:
Engine computer function that keeps the air/fuel mixture as close to the ideal 14.7:1 stoichiometric ratio as possible
Ground (GND):
An electrical conductor used as a common return for an electric circuit(s) and with a relative zero potential (voltage).
Hall Effect Sensor:
Any of a type of sensor utilizing a permanent magnet and a transistorized Hall Effect switch. Hall Effect type sensors may be used to measure speed and position of the crankshaft or camshaft — for spark timing and fuel injector control.
HC:
Hydrocarbons
HEI:
High Energy Ignition
HO2S:
Heated Oxygen Sensor. See O2S.
HVAC:
Heating, Ventilation & Air Conditioning (System)
I/M:
Inspection and Maintenance. An emission control program.
IAC:
Idle Air Control. A device mounted on the throttle body which adjusts the amount of air bypassing a closed throttle so that the PCM can control idle speed.