2WD:  2 Wheel Drive

4WD:  4 Wheel Drive

4WS:  4 Wheel Steering (Very few cars had this, no mass produced cars really use this)

2V:  2 Valve (Older cylinder heads, Mostly American cars)

4V:  4 Valve (Most common cylinder head set-up)

5V:  5 Valve (Found in some European cylinder heads)

AAT:  Ambient Air Temperature

ABS:  Antilock Brake System

AC:  Air Conditioning

ACC:  Adaptive Cruise Control also Automatic Climate Control

A/F sensor:  Air Fuel Sensor

AFR:  Air Fuel Ratio

alt:  Alternator

ARS:  Automatic Restraint System

ARC:  Automatic Ride Control

A/T:  Automatic Transmission

ATC:  Automatic Temperature Control

ATF: Automatic Transmission Fluid

AWD:  All Wheel Drive

AYC:  Active Yaw Control

Baro:  Barometric pressure. Usually a sensor.

batt:  Battery

BCM:  Body Control Module

BHP:  Brake Horsepower

BTDC:  Before Top Dead Center

CAA:  Clean Air Act

CAFE:  Corporate Average Fuel Economy (USA)

CEL:  Check Engine Light

CFI:  Central Fuel Injection

CFM:  Cubic Feet Per Minute

CG: Center of Gravity

CID:  Cubic Inch Displacement

CKP Crankshaft Position

CL:  Closed Loop

cmd:  Command

CMP:  Camshaft Position

CNG:  Compressed Natural Gas

CO:  Carbon Monoxide

comm:  Communication

CO2:  Carbon Dioxide

COP:  Coil On Plug

CPU:  Central Processing Unit

CTS:  Coolant Temperature Sensor

CV:  Constant Velocity

CVT:  Continuously Variable Transmission

dB:  Decibels

DC:  Direct Current

DFI:  Direct Fuel Injection

diff:  Differential

DIS:  Direct Ignition System

dist:  Distributor

DLC:  Data Link Connector

DMM:  Digital MultiMeter

DOHC:  Dual Overhead Cam

DPFE:  Differential Pressure Feedback (Ford EGR)

DRL:  Daytime Running Lights

DTC:  Diagnostic Trouble Code

DVOM:  Digital Volt Ohm Meter

E4OD:  Electronic 4-speed Overdrive transmission

E10:  Ethanol 10%

E85:  Ethanol 85%

EAS:  Electronically Assisted Steering

ECBM:  Electronic Brake Control Module

ECM:  Engine Control Module

ECM:  Electronic Control Module

ECS:  Emission Control System

ECT:  Engine Coolant Temperature

ECU:  Electronic Control Module

EDR:  Even Data Recorder

EEC:  Electronic Engine Control

EPROM:  Erasable Programable Read Only Memory

EFE:  Early Fuel Evaporation

EFI:  Electronic Fuel Injection

EGR:  Exhaust Gas Recirculation

ELC:  Electronic Level Control

EPA:  Environment Protection Agency

EPC:  Electronic Pressure Control

ESC:  Electronic Spark Control

ELD:  Electronic Load Detection

ESP:  Electronic Stability Program

ETC:  Electronic Temperature Control

ETS:  Electronic Traction System

EV:  Electric Vehicle

EVAP:  Evaporative Emissions

FBC:  Feedback Carburetor

FF:  Flex Fuel

FFV:  Flexible Fuel Vehicle

FM:  Frequency Modulated

FPS:  Fast Pass Standard

freq:  Frequency

FT:  Fuel Trim

FTP:  Fuel Tank Pressure

FTPT:  Fuel Tank Pressure Transducer

GAWR:  Gross Axle Weight Rating

GND:  Ground

GPCM:  Glow Plug Control Module

GPS:  Global Positioning System

GVW:  Gross Vehicle Weight

GVWR:  Gross Vehicle Weight Rating

H2O:  Water

HC:  Hydrocarbons

HD:  Heavy Duty

HDR:  Hight Data Rate

HEGO:  Heated Exhaust Gas Oxygen sensor (Now HO2S)

HEV:  Hybrid Electric Vehicle

Hg:  Mercury

HID:  High Intensity Discharge

HO:  High Output

HO2S:  Heated Oxygen Sensor

hp:  Horsepower

HVAC:  Heating Ventilation and Air Conditioning

Hz:  Hertz

IA:  Intake Air

IAC:  Idle Air Control

IAT:  Intake Air Temperature

iATN:  INternational Automotive Technicians Network

IC:  Integrated Circuit

IC:  Ignition Control

ID:  Identification

ID:  Inside Diameter

IDI:  Integrated Direct Ignition

IDM:  Ignition Diagnostic Module

IDM:  Injector Driver Module

IDS:  Integrated Diagnostic Software

IGN:  Ignition

I/M:  Inspection Maintenance

IMA:  Integrated Motor Assist

INJ: Injector

int:  Interior

I/O:  In/Out

IAC:  Idle Air Control

i-VTEC:  Intelligent Variable Valve Timing Electronic Control

KAM:  Keep Alive Memory

KAPWR:  Keep Alive Memory Power

kg:  Kilogram

kg/h:  Kilograms per Hour

km:  Kilometer

km/h:  Kilometer per Hour

km/l:  Kilometers per Liter

KOEO:  Key Off Engine On

KOER:  Key On Engine Running

kPa:  Kilopascal

KS:  Knock Sensor

kv:  Kilovolts

L:  Liter

L4:  Inlie 4 cylinder engine

LCD:  Liquid Crystal Display

LCM:  Lighting Control Module

LDR:  Low Data Rate

LED:  Light Emitting Diode

LEP:  Light Emitting Polymer (glows in the dark)

LEV:  Low Emissions Vehicle

Lm:  Lumens

LNG:  Liquid Natural Gas

LPG:  Liquid Petroleum Gas

LPM:  Liters Per Minute

LPS:  Low Pressure Sensor

LSD:  Limited Slip Differential

LSUV:  Luxury Sport Utility Vehicle

LT:  Long Term (Fuel Trim)

LTPWS:  Low Tire Pressure Warning System

MAF:  Mass Airflow Sensor

MAP:  Manifold Absolute Pressure

MAT:  Manifold Air Temperature

MC:  Mixture Control

MCU:  Microprosessor Control Unit

MFI:  Multiport Fuel Injection

MGMT:  Management

MIL: Malfunction Indicator Lamp

mm:  Millimeter

MSRP:  Manufacturer Suggested Retail Price

M/T:  Manual Transmission

mV:  Milivolt

MV:  Megavolt

NC:  Normally Closed

NCAP:  New Car Assessment Program

NAVI:  Navigation

NEG:  Negative

NEU:  Neutral

NG:  Natural Gas

NGV:  Natural Gas Vehicle

NO:  Normally Open

NOx:  Nitrogen Oxides

NPF:  No Problem Found

NPTC:  National Pipe Thread Coarse

NPTF  National Pipe Thread Fine

NV:  Night Vision

O2:  Oxygen

O2S:  Oxygen Sensor

OBD:  On Board Diagnostics

OBDII:  On Board Diagnostics generation 2

OBDIII:  On Board Diagnostics generation 3

OCC:  Output Circuit Check

OCR:  Oil Control Ring

OD:  Outside Diameter

OD:  OverDrive

ODO:  Odometer

OE:  Original Equipment

OEM:  Original Equipment Manufacturer

OHC:  Overhead Cam

OL:  Open Loop

PASS:  Passenger

PB:  Power Brakes

PC:  Pressure Control

PCI:  Programable Controller Interface

PCM:  Powertrain Control Module

PFE:  Pressure Feedback EGR

PGMFI:  Programable Multiport Fuel Injection

PID:  Parameter Identification

PIM:  Power Inverter Module

PIP:  Profile Ignition Pickup (also CKP Crank Position)

POS:  Positive

POT:  Potentiometer

ppm:  Parts Per Million

PRNDL:  Park Reverse Neutral Drive Low

PROM:  Programable Read Only Memory

PS:  Power Steering

PSA:  Pressure Switch Assembly

psgr:  Passenger

psi:  Pounds Per Square Inch

psi a:  Ponds Per Square Inch Absolute

psig:  Pounds Per Square Inch Gauge

PSP:  Power Steering Pressure

PTC:  Pending Trouble Code

PTC:  Positive Temperature Coefficient

PTO:  Power Take Off

PWM:  Pulse Width Modulation

PWR:  Power

RAM:  Random Access Memory

rec:  Receive

REDOX:  Reduction Oxidation Catalytic Converter

REF:  Reference

RFI:  Radio Frequency Interference

RFID:  Radio Frequency Identification

Rly:  Relay

RM:  Relay Module

R&R:  Remove and Replace

RSC:  Roll Stability Control

RTV:  Room Temperature Vulcanizing

RV:  Recreational Vehicle

RWD:  Rear Wheel Drive

SAE:  Society of Automotive Engineers

SDL:  Serial Data LInk

SEFI:  Sequential Electronic Fuel Injection

SEMA:  Special Equipment Market Association

SES:  Service Engine Soon

SFI:  Sequential Fuel Injection

SHO:  Super Hight Output

SIR:  Supplemental Inflatable Restraint

SNSR:  Sensor

SO2:  Sulphur Dioxide

SOC:  State of Change

sol:  Solenoid

S/P:  Series Parallel

SPD:  Speed

SRS:  Supplemental Restraint System

SSV:  Shift Solenoid Valve

ST:  Short Term (fuel trim)

stdby:  Standby

SUV:  Sport Utility Vehicle

sw:  Switch

SWPS:  Steering Wheel Position Sensor

TACH:  Tachometer

TB:  Throttle Body

TBI:  Throttle Body Injection

TC:  Transmission Control

TCC:  Torque Converter Clutch

TCM:  Transmission Control Module

TCS:  Traction Control System

TCU:  Transmission Control Unit

TDC:  Top Dead Center

TEMP:  Temperature

TFI:  Thick Film Integrated (Ford Ignition)

TFT:  Transmission Fluid Temperature

torq:  Torque

TP:  Throttle Position

TPI:  Tuned Port Injection

TPMS:  Tire Pressure Monitoring System

TPS:  Throttle Position Sensor

trans:  Transmission

TSB:  Technical Service Bulletin

TSS:  Transmission Speed Sensor

TV:  Throttle Valve

TVS:  Thermal Vacuum Switch

TWC:  Three Way Catalyst

U/H:  Under Hood

ULEV:  Ultra Low Emissions Vehicle

ULSD:  Ultra Low Sulphur Diesel

unlk:  Unlock

V:  Volts

VAC:  Vacuum

VAF:  Vane Air Flow

VAPS:  Variable Assist Power Steering

VB:  Valve Body

VCM:  Vehicle Communication Module

VCT:  Variable Camshaft Timing

VCDS:  Vehicle Dynamics Control System

VDR:  Vehicle Data Recorder

veh:  Vehicle

vel:  Velocity

ver:  Version

vert:  Vertical

VIN:  Vehicle Identification Number

VSS:  Vehicle Speed Sensor

VSV:  Vacuum Solenoid Valve

VTEC:  Variable Timing and Electronic Control

VVT-i:  Variable Valve Timing with Intelligence

VVTL-i:  Variable Valve Timing and Lift with Intelligence

w/:  With

w/o:  Without

WOT:  Wide Open Throttle

WSS:  Wheel Speed Sensor

X-valve:  Expansion Valve

ZEV:  Zero Emissions Vehicle