Automotive Definitions and Acronyms

The automotive industry loves abbreviations and acronyms. Take for instance this conversation recently overheard, "Your MAF has failed and the ECM is setting a DTC."

What the ...?

Well, this is why we created this list, to help decipher what all these things mean. Next to each acronym you will find a brief description, and we will link to additional information as it becomes available.

Acronym Definition
A/C Air Conditioning
A/F Air/Fuel Ratio
A/T Automatic Transmission or Transaxle
ABS Anti-Lock Brake System
AC Alternating Current
AIR Secondary Air Injection
ATDC After Top Dead Center
ATF Automatic Transmission Fluid
AWD All-Wheel Drive
B1 Bank 1
B1 S1 Bank 1 Sensor 1
B1 S2 Bank 1 Sensor 2
B2 Bank 2
B2 S1 Bank 2 Sensor 1
B2 S2 Bank 2 Sensor 2
B+ Battery Positive Voltage (12 Volts)
BMW Bayerische Motoren Werke (Bavarian Motor Works)
BARO Barometric Pressure (Atmospheric Pressure)
BAT Battery
BCM Body Control Module
BHP Brake Horsepower
BTC Before Top Center
BTDC Before Top Dead Center
BTU British Thermal Units
C Celsius
CAC Charge Air Cooler (Inter-Cooler)
CC Cubic Centimeters
CFI Continuous Fuel Injection
CFM Cubic Feet per Minute
CID Cubic Inch Displacement
CIS Continuous Injection System
CIS-E Electronic Continuous Injection System
CKP Crankshaft Position Sensor
CL Closed Loop
CMP Camshaft Position Sensor
CO Carbon Monoxide
CO2 Carbon Dioxide
CPP Clutch Pedal Position
CTP Closed Throttle Position
dB Decibels
DC Direct Current
DFI Direct Fuel Injection
DLC Data Link Connector
DOHC Dual Overhead Cams
DTC Diagnostic Trouble Code
DTM Diagnostic Test Mode
DVOM Digital Volt Ohm Meter
EBCM Electronic Brake Control Module
EBTCM Electronic Brake Traction Control Module
EC Engine Control
ECM Engine Control Module
ECT Engine Coolant Temperature
EFE Early Fuel Evaporation
EGR Exhaust Gas Recirculation
EGRT EGR Temperature
EI Electronic Ignition
EM Engine Modification
EMI Electromagnetic Interference
EVAP Evaporative Emission System
F Fahrenheit
FC Fan Control
FF Flexible Fuel
FP Fuel Pump
FPROM Flash Erasable PROM
FT Fuel Trim (Fuel Mixture)
ft. lb. Foot Pound (Unit of Measure for Torque)
FTP Federal Test Procedure
FWD Front-Wheel Drive
gal Gallon
GEN Generator
GND Ground
GPM Grams per Mile
H20 Water
HC Hydrocarbon
Hg Mercury (Unit of Measure for Vacuum)
HO2S Heated Oxygen Sensor
HO2S1 Upstream Heated Oxygen Sensor
HO2S2 Up or Downstream Heated Oxygen Sensor
HO2S3 Downstream Heated Oxygen Sensor
HP Horsepower
HVAC Heating Ventilation and A/C System
HVS High Voltage Switch
I/M Inspection/Maintenance
I/P Instrument Panel
IA Intake Air
IAC Idle Air Control
IAT Intake Air Temperature
IC Ignition Control Circuit
ICM Ignition Control Module
ID Inside Diameter
IFS Inertia Fuel Shutoff
IGN Ignition
IPC Instrument Panel Cluster
ISC Idle Speed Control
kHz Kilohertz
Km Kilometers
KOEC Key On, Engine Cranking
KOEO Key On, Engine Off
KOER Key On, Engine Running
kPa Kilopascals
KS Knock Sensor
KV Kilovolts
L Liters
lb. ft. Pound Feet
LT Long Term Fuel Trim
MAF Mass Airflow Sensor
MAP Manifold Absolute Pressure Sensor
MC Mixture Control
MFI Multiport Fuel Injection
MIL Malfunction Indicator Lamp
mm Millimeters
MPG Miles per Gallon
MPH Miles per Hour
ms Millisecond (1/1000 of a Second)
mV Millivolts
Nm Newton Meters
NOX Oxides of Nitrogen
O2S Oxygen Sensor
OBD Onboard Diagnostics
OBD I Onboard Diagnostics, First Generation
OBD II Onboard Diagnostics, Second Generation
OC Oxidation Catalyst
OD Outside Diameter
ODM Output Device Monitor
OE Original Equipment
OEM Original Equipment Manufacturer
OHC Overhead Cam
OL Open Loop
P/B Power Brakes
P/N Part Number
P/S Power Steering
PAIR Pulsed Secondary Air Injection
PCM Powertrain Control Module
PCV Positive Crankcase Ventilation
PNP Park/Neutral Switch
PPM Parts per Million
PROM Programmable Read Only Memory
PSA Pressure Switch Assembly
PSI Pounds per Square Inch
PSP Power Steering Pressure
pt. Pint
Qt. Quart
RAM Random Access Memory
RFI Radio Frequency Interference
ROM Read Only Memory
RPM Revolutions per Minute
RWD Rear-Wheel Drive
SC Supercharger
SCB Supercharger Bypass
SFI Sequential Fuel Injection
SOHC Single Overhead Cam
SRI Service Reminder Indicator
SRT System Readiness Test
ST Short Term Fuel Trim
TACH Tachometer
TB Throttle Body
TBI Throttle Body Injection
TC Turbocharger
TCC Torque Converter Clutch
TCCM Transfer Case Control Module
TCM Transmission or Transaxle Control Module
TDC Top Dead Center
TFP Throttle Fluid Pressure
TP Throttle Position
TPS Throttle Position Sensor
TVV Thermal Vacuum Valve
TWC Three Way Catalyst
TWC+OC Three Way + Oxidation Catalytic Converter
V Volts
VATS Vehicle Anti-Theft System
VAC Volts Alternating Current
VAF Volume Airflow
VDC Volts Direct Current
VIN Vehicle Identification Number
VR Voltage Regulator
VS Vehicle Sensor
VSS Vehicle Speed Sensor
WOT Wide Open Throttle
WU-TWC Warm Up Three-Way Catalytic Converter

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