OBD-II / Automotive Acronyms & Definitions

This is the place where we tell you what various acronyms stand for, and what some other technical words mean.

A through G

• ABS - Anti-lock Braking System
• A/C - Air Conditioning
• AIR - Secondary Air Injection System
• BARO - Barometric Pressure
• CKP - Crankshaft Position Sensor
• CMP - Camshaft Position Sensor
• CEL - Check Engine Light - same as Malfunction Indicator Lamp (MIL) or Service Engine Soon
• CO - Carbon Monoxide
• CO2 - Carbon Dioxide
• DEPS - Digital Engine Position Sensor
• DLC - Data Link Connector
• DIS - Distributor-less Ignition System
• DTC - Diagnostic Trouble Code
• ECT - Engine Coolant Temperature
• EEPROM - Electrically Eraseable Programmable Read Only Memory
• EGR - EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor (DPF). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc.
• EVAP - Evaporative Emmissions System
• FTP - Federal Test Procedure

H through M

• H2O - Water
• HO2S - Heated Oxygen Sensor
• HC - Hydrocarbon
• HVS - High Voltage Switch
• IAC - Idle Air Controller
• IAT - Intake Air Temperature
• IC - Ignition Control
• I/M - Inspection/Maintenance
• KS - Knock Sensor
• MAF - Mass Air Flow (Sensor)
• MAP - Manifold Absolute Pressure
• MIL - Malfunction Indicator Lamp - same as Check Engine Light or Service Engine Soon
• MR - Magneto-Resistive
• MSC - Mass Storage Cartridge

N through T

• NOx - Oxides of Nitrogen
• OBD - OnBoard Diagnostics
• OBD-I - On-Board Diagnostics Generation One
• OBD-II - On-Board Diagnostics Generation Two
• OBPA - Off-Board Programming Adapter
• O2S - Oxygen Sensor
• OSC - Oxygen Storage Capacity
• PCM - Powertrain Control Module
• SES - Service Engine Soon - same as Malfunction Indicator Lamp (MIL) or Check Engine Light (CEL)
• SPS - Service Programming System
• TCC - Torque Converter Clutch
• TDC - Top Dead Center
• TP - Throttle Position or;
• TPS - Throttle Position Sensor
• TWC - Three Way Catalyst

U through Z

• UART - Universal Asychronious Receive & Transmit
• VCM - Vehicle Control Module
• VIM - Vehicle Interface Module
• VPW - Variable Pulse Width
• VSS - Vehicle Speed Sensor
• WOT - Wide Open Throttle