O2 - Oxygen sensor.
Open Loop - When the ECM operates w/o the O2 reading input.
Closed Loop - When the ECM operates w/ the O2 reading input.
TPS - Throttle Position Sensor
IAC - Idle Air Control
MAT - Manifold Air Temp.
CTS - Coolant Temp. Sensor
WOT - Wide Open Throttle
PE - Power Enrichment
ROM - Read Only Memory
PROM - Programmable ROM
EPROM - Eraseable PROM (What comes stock in most ECMs)(Requires UV light eraser)
EEPROM - Electronically Eraseable PROM (What most people are upgrading to)(Eraseable by burner)
AIR - Air Injection Reaction
CCP - Charcoal Canister Purge
EGR - Exhaust Gas Recirculation
VSS - Vehicle Speed Sensor
TCC - Torque Converter Control
FPR - Fuel Pressure Regulator
AFPR - Adjestable FPR
TPI - Tuned Port Injection
HEI - High Energy Ignition
ESC - Electronic Spark Control (Knock Sensor)
EST - Electronic Spark Timing
MAP - Manifold Absolute Pressure
MAF - Mass Air Flow
ECM - Engine Control Module