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 |
| EPROM | Erasable PROM |
| 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 |
