MODE Encyclopedia

An anti-lock braking system (ABS) is a safety anti-skid braking system used on aircraft and on land vehicles, such as cars, motorcycles, trucks, and buses. ABS operates by preventing the wheels from locking up during braking, thereby maintaining tractive contact with the road surface and allowing the driver to maintain more control over the vehicle.

Adaptive cruise control (ACC) is a type of advanced driver-assistance system for road vehicles that automatically adjusts the vehicle speed to maintain a safe distance from vehicles ahead. As of 2019, it is also called by 20 unique names that describe that basic functionality. This is also known as Dynamic cruise control.

An automatic transmission (sometimes abbreviated AT) is a multi-speed transmission used in motor vehicles that does not require any input from the driver to change forward gears under normal driving conditions. Vehicles with internal combustion engines, unlike electric vehicles, require the engine to operate in a narrow range of rates of rotation, requiring a gearbox, operated manually or automatically, to drive the wheels over a wide range of speeds.

An all-wheel drive vehicle (AWD vehicle) is one with a powertrain capable of providing power to all its wheels, whether full-time or on-demand.

In automotive electronics, body control module (BCM) or 'body computer' is a generic term for an electronic control unit responsible for monitoring and controlling various electronic accessories in a vehicle's body. Typically in a car the BCM controls the power windows, power mirrors, air conditioning, immobilizer system, central locking, etc. The BCM communicates with other on-board computers via the car's vehicle bus, and its main application is controlling load drivers – actuating relays that in turn perform actions in the vehicle such as locking the doors, flashing the turn signals (in older cars), or dimming the interior lighting.

bootmod3 (bm3) is a widely adopted cloud based tuning platform for BMW F/G series, Mini Marquee and 2019+ Toyota Supra vehicles. It offers fast flashing, custom ROMs, and a live dashboard with hundreds of datalog channels. The platform is available on iOS, Android, Windows, and macOS.

A bricked ECU (BRICK) is where a corrupt flash, incompatible operating system/Calibration or failed update has caused the ECU to no longer function correctly, in most circumstances an event like that results in the ECU being unable to communicate to scantools or be reflashed.

A blowoff valve (BOV) (also called dump valve or compressor bypass valve) is a pressure release system present in most petrol turbocharged engines. Blowoff valves are used to reduce pressure in the intake system as the throttle is closed, thus preventing compressor surge.

A cold air intake (CAI) is usually an aftermarket assembly of parts used to bring relatively cool air into a car's internal-combustion engine.

A catalytic converter (CAT) is an exhaust emission control device which converts toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalyzing a redox reaction. Catalytic converters are usually used with internal combustion engines fueled by gasoline or diesel, including lean-burn engines, and sometimes on kerosene heaters and stoves.

Cat or Catted refers to the Catalytic Converter commonly found within the downpipe, front pipe or mid pipe.

The centerbore (CB) of a wheel is the hole in the center of the wheel that centers it over the mounting hub of the car. Some factory wheels have a centerbore that matches exactly with the hub to reduce vibration by keeping the wheel centered. Wheels with the correct centerbore for the car they will be mounted on are known as hubcentric. Hubcentric wheels reduce the job of the lug nuts to center the wheel on the hub. Wheels that are not hubcentric are known as lugcentric, as the job of centering is done by the lug nuts assuming they are properly torqued down. Another, more common, term is hub piloted or stud piloted wheels and hubs. The stud piloted (lug centeric) is an older design while the hub piloted design is more commonly in use today and can provide for a more accurate connection.

A check engine light (CEL) or malfunction indicator lamp (MIL), is a tell-tale that a computerized engine-management system used to indicate a malfunction or problem with the vehicle ranging from minor (such as a loose gas cap) to serious (worn spark plugs, engine problems or a faulty oil valve, etc.). Found on the instrument panel of most automobiles, it usually bears the legend engine, check engine, service engine soon, maintenance required, emiss maint, or a pictogram of an engine—and when illuminated, it is typically an amber or red color.

The light generally has two stages: steady (indicating a minor repairable fault, but service on the vehicle is strongly recommended as soon as possible to prevent future damage) and flashing (indicating a severe fault and an emergency that makes the vehicle unsafe to drive and it is strongly recommended that the vehicle gets mechanical attention straight away). When the MIL is lit, the engine control unit stores a fault code related to the malfunction, which can be retrieved—although in many models this requires the use of a scan tool. This warning light can indicate almost anything from a loose gas cap to a serious knock or fault in the engine.

Most modern centerlock (CL) wheels are fastened to the hub by a single large hex nut. A hollow, tapered shaft centers the wheel on the hub. Torque is transmitted by pins and matching holes at the hub-wheel interface. The retaining nut requires a large amount of torque to secure, therefore a long-handled torque wrench or a powerful impact wrench (also called a "wheel gun") is used to tighten it. Wheels of this type are used on many modern racing cars, including NASCAR, Formula One and racing sports cars.

In machining, numerical control, also called computer numerical control (CNC), is the automated control of tools by means of a computer. It is used to operate tools such as drills, lathes, mills, grinders, routers and 3D printers. CNC transforms a piece of material (metal, plastic, wood, ceramic, stone, or composite) into a specified shape by following coded programmed instructions and without a manual operator directly controlling the machining operation.

Cells per square inch (CPSI) refers to the amount of cells per square inch in the catalyst, 200cpsi would be considered a sport cat whereas 600cpsi would be considered restrictive.

A catalytic converter is an exhaust emission control device which converts toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalyzing a redox reaction. Catalytic converters are usually used with internal combustion engines fueled by gasoline or diesel, including lean-burn engines, and sometimes on kerosene heaters and stoves.

Some exhaust systems are Decatted (DE-CAT) (called catless or de-cat systems) eliminate the catalytic converter commonly found within the downpipe, front pipe or mid pipe.

A catalytic converter is an exhaust emission control device which converts toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalyzing a redox reaction. Catalytic converters are usually used with internal combustion engines fueled by gasoline or diesel, including lean-burn engines, and sometimes on kerosene heaters and stoves.

A dual-clutch transmission (DCT) (sometimes referred to as a twin-clutch transmission) is a type of multi-speed vehicle transmission system, that uses two separate clutches for odd and even gear sets. The design is often similar to two separate manual transmissions with their respective clutches contained within one housing, and working as one unit. In car and truck applications, the DCT functions as an automatic transmission, requiring no driver input to change gears.

Direct Injection (DI) or Gasoline direct injection (GDI), also known as petrol direct injection (PDI), is a mixture formation system for internal combustion engines that run on gasoline (petrol), where fuel is injected into the combustion chamber. This is distinct from manifold injection systems, which inject fuel into the intake manifold (inlet manifold).

A Digital motor electronics (DME) also called engine control unit (ECU), also called an engine control module (ECM), is a device which controls multiple systems of an internal combustion engine in a single unit. Systems commonly controlled by an ECU include the fuel injection and ignition systems.

A downpipe (DP) (also called Dump Tubes or Dump Pipes), are a portion of exhaust mounted directly off theturbocharger. They provide a means for exhaust gasses to leave the turbine housing and enter the main exhaust system. Downpipes also house the oxygen sensors on. Some systems (called catless or de-cat systems) eliminate the catalytic converter.

A diesel particulate filter (DPF) is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine.

This may also be referred to as a GPF (Gasoline Particulate Filter), OPF (On-Board Particulate Filter) or PPF (Petrol Particulate Filter).

A daytime running lamp (DRL, also daytime running light) is an automotive lighting and bicycle lighting device on the front of a road going motor vehicle or bicycle. It is automatically switched on when the vehicle's handbrake has been pulled down, when the vehicle is in gear, or when the engine is started, emitting white, yellow, or amber light. Their intended use is not to help the driver see the road or their surroundings, but to help other road users identify an active vehicle.

Electronic stability control (ESC), also referred to as electronic stability program (ESP) or dynamic stability control (DSC), is a computerized technology that improves a vehicle's stability by detecting and reducing loss of traction (skidding). When ESC detects loss of steering control, it automatically applies the brakes to help steer the vehicle where the driver intends to go. Braking is automatically applied to wheels individually, such as the outer front wheel to counter oversteer, or the inner rear wheel to counter understeer. Some ESC systems also reduce engine power until control is regained. ESC does not improve a vehicle's cornering performance; instead, it helps reduce the chance of the driver losing control of the vehicle.

A direct-shift gearbox (DSG, German: Direktschaltgetriebe) is an electronically controlled, dual-clutch, multiple-shaft, automatic gearbox, in either a transaxle or traditional transmission layout (depending on engine/drive configuration), with automated clutch operation, and with fully-automatic or semi-manual gear selection. The first dual-clutch transmissions were derived from Porsche in-house development for the Porsche 962 in the 1980s.

The Diagnostic Trouble Codes (DTC's) of OBD-I vehicles can usually be found without an expensive scan tool. Each manufacturer used their own Diagnostic Link Connector (DLC), DLC location, DTC definitions, and procedure to read the DTC's from the vehicle. DTC's from OBD-I cars are often read through the blinking patterns of the 'Check Engine Light' (CEL) or 'Service Engine Soon' (SES) light. By connecting certain pins of the diagnostic connector, the 'Check Engine' light will blink out a two-digit number that corresponds to a specific error condition.

An electronic control unit (ECU), also known as an electronic control module (ECM), is an embedded system in automotive electronics that controls one or more of the electrical systems or subsystems in a car or other motor vehicle.

An electronic control unit (ECU), also known as an electronic control module (ECM), is an embedded system in automotive electronics that controls one or more of the electrical systems or subsystems in a car or other motor vehicle.

Electronic Fuel injection (EFI) is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines.

In internal combustion engines, exhaust gas recirculation (EGR) is a nitrogen oxide (NOx) emissions reduction technique used in petrol/gasoline, diesel engines and some hydrogen engines. EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders. The exhaust gas displaces atmospheric air and reduces O2 in the combustion chamber. Reducing the amount of oxygen reduces the amount of fuel that can burn in the cylinder thereby reducing peak in-cylinder temperatures. The actual amount of recirculated exhaust gas varies with the engine operating parameters.

Electronic stability control (ESC), also referred to as electronic stability program (ESP) or dynamic stability control (DSC), is a computerized technology that improves a vehicle's stability by detecting and reducing loss of traction (skidding). When ESC detects loss of steering control, it automatically applies the brakes to help steer the vehicle where the driver intends to go. Braking is automatically applied to wheels individually, such as the outer front wheel to counter oversteer, or the inner rear wheel to counter understeer. Some ESC systems also reduce engine power until control is regained. ESC does not improve a vehicle's cornering performance; instead, it helps reduce the chance of the driver losing control of the vehicle.

Electronic stability control (ESC), also referred to as electronic stability program (ESP) or dynamic stability control (DSC), is a computerized technology that improves a vehicle's stability by detecting and reducing loss of traction (skidding). When ESC detects loss of steering control, it automatically applies the brakes to help steer the vehicle where the driver intends to go. Braking is automatically applied to wheels individually, such as the outer front wheel to counter oversteer, or the inner rear wheel to counter understeer. Some ESC systems also reduce engine power until control is regained. ESC does not improve a vehicle's cornering performance; instead, it helps reduce the chance of the driver losing control of the vehicle.

The offset is the distance from the hub-mounting surface to the wheel's true centerline. It is quantified by an ET value (from the German Einpresstiefe, literally press-in depth) and measured in mm. A positive offset means the hub-mounting surface is closer to the outside edge of the wheel, while a negative offset means the hub-mounting surface is closer to the inside edge of the wheel.-mounting surface is closer to the outside edge of the wheel, while a negative offset means the hub-mounting surface is closer to the inside edge of the wheel.

An electric vehicle (EV) is a vehicle that uses one or more electric motors for propulsion. The vehicle can be powered by a collector system, with electricity from extravehicular sources, or can be powered autonomously by a battery or by converting fuel to electricity using a generator or fuel cells. EVs include road and rail vehicles, electric boats and underwater vessels, electric aircraft and electric spacecraft.

An electronic wastegate (EWG) allows a boost control strategy that reduces exhaust backpressure caused by the turbocharger by opening the wastegate when turbo boost is not needed, resulting in improved fuel economy. The wastegate is also held open during cold starting to lower emissions by speeding up initial catalyst light-off.

E85 (Ethanol Fuel Blend 85%) is an abbreviation typically referring to an ethanol fuel blend of 85% ethanol fuel and 15% gasoline or other hydrocarbon by volume.

An automotive facelift (FL), also known as mid-generational refresh, minor model change, minor model update, or life cycle impulse, comprises changes to a vehicle's styling during its production run including, to highly variable degree, new sheetmetal, interior design elements or mechanical changes, allowing a carmaker to freshen a model without a complete redesign. While the life cycle of cars hovers around six to eight years until a full model change, facelifts are generally introduced around three years in their production cycle.

A facelift retains the basic styling and platform of the car,with aesthetic alterations, e.g., changes to the front fascia (grille, headlights), taillights, bumpers, instrument panel and center console, and various body or interior trim accessories. Mechanical changes may or may not occur concurrently with the facelift (e.g., changes to the engine, suspension or transmission).

Engine Flash tuning (FLASH) is the adjustment or modification of the internal combustion engine or Engine Control Unit (ECU) to yield optimal performance and increase the engine's power output, economy, or durability. These goals may be mutually exclusive; an engine may be de-tuned with respect to output power in exchange for better economy or longer engine life due to lessened stress on engine components.

Front-wheel drive (FWD) is a form of engine and transmission layout used in motor vehicles, in which the engine drives the front wheels only. Most modern front-wheel-drive vehicles feature a transverse engine, rather than the conventional longitudinal engine arrangement generally found in rear-wheel-drive and four-wheel-drive vehicles.

A diesel particulate filter (DPF) is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine.

This may also be referred to as a GPF (Gasoline Particulate Filter), OPF (On-Board Particulate Filter) or PPF (Petrol Particulate Filter).

Horsepower (HP) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are the imperial horsepower as in “HP” or “BHP” which is about 745.7 watts, and the metric horsepower as in “CV” or “PS” which is approximately 735.5 watts.

High-pressure mechanical pumps Pumps or High-pressure Fuel Pumps (HPFP) for modern direct-injection engines operate at a much higher pressure, up to 30,000 psi (2,100 bar) and have configurations such as common rail radial piston, common rail two piston radial, inline, port and helix, and metering unit. Injection pumps are fuel lubricated which prevents oil from contaminating the fuel.

An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons (piston engine), turbine blades (gas turbine), a rotor (Wankel engine), or a nozzle (jet engine). This force moves the component over a distance. This process transforms chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to.

Intake air temperature sensor (IAT sensor) to allow the engines ECU to calculate the density of the air, and the fuel delivery accordingly.