
The following list of emissions-related acronyms has been
standardized by the Society of Automotive Engineers to help
servicing today's vehicles easier (or at least more
comprehendible). The common terminology, which is part of SAE
standard 1930, is being adopted by all vehicle manufacturers.
ACL
Air Cleaner and/or filter
CKP
Crankshaft Position sensor
CL
Closed Loop (feedback mode)
DCL
Data Link Connector
DTC
Diagnostic Trouble Code (fault code)
ECT
Engine Coolant Sensor
EGR
Exhaust Gas Recirculation
EI
Electronic Ignition system
EPROM
Erasable Programmable Read Only Memory
EEPROM
Electronically Erasable Programmable Read Only Memory
EVAP
Evaporative emission control system
HO2S
Heated Oxygen Sensor
IAC
Idle Air Control
IAT
Intake Air Temperature Sensor
IC
Ignition Control (electronic spark timing)
KS
Knock Sensor
LTFT
Long Term Fuel Trim
MAP
Manifold Absolute Pressure sensor
MIL
Malfunction Indicator Lamp (Service Engine Soon lamp)
MFI
Multiport Fuel Injection system
O2S
Oxygen Sensor
OBD
On-Board Diagnostic system check
OC
Oxidation catalyst
OL
Open Loop (feedback mode)
PCM
Powertrain Control Module
PCV
Positive Crankcase Ventilation
PNP
Park Neutral Position switch
RPM
Revolutions per Minute
SFI
Sequential Fuel Injection system
STFT
Short Term Fuel Trim
STD
Scan Tool Data
TCC
Torque Converter Clutch
TP
Throttle Position sensor
TWC
Three-Way Converter (HC, CO & NOX)
TWC+OC
Three-Way Converter plus Oxidation Converter
VIN
Vehicle Identification Number
VSS
Vehicle Speed Sensor
WU-OC
Warm Up Oxidation Converter
WU-TWC
Warm Up Three-Way Converter