Terminology

ACP

Audio Control Protocol is the communications protocol for audio and entertainment systems

AICM

Auxiliary Idle Control Module, also called Auxiliary Powertrain Control Module (APCM), is for use in Light Trucks equipped with 7.3L DIT Diesel engines to elevate engine speed for increased power output at idle and to maintain battery charge

Actuator

A device which delivers motion in response to an electrical signal.

Additive

A compound that enhances some property of, or imparts some new property to, the base fluid. In some hydraulic fluid formulations, the additive volume may constitute as much as 20 percent of the final composition. The more important types of additives include anti-oxidants, anti-wear additives, corrosion inhibitors, viscosity index improvers, and foam suppressants.

Aeration

The state of air being suspended in a liquid such as a lubricant or hydraulic fluid.

Aftercooler

A heat exchanger used to cool compressed induction air from turbocharging or supercharging. It reduces the charged air temperature by transferring heat from the charge air to a cooling medium such as air or coolant.

Ambient Temperature

The environmental air temperature in which something operates in. Typically it is a measurement of the air temperature in the shade with no solar radiation or wind.

Ampere - Amp

The standard unit for measuring the strength of an electrical current.

Analog

A continuously variable voltage.

APS - Accelerator Position Sensor

A potentiometer style sensor that indicates the operator's pedal position.

AWA Feature

A feature built into the high pressure oil rails used to dampen noises that can be caused by the hydraulic system.

BARO/BAP - Barometric Absolute Pressure Sensor

A variable capacitance sensor which when supplied with a 5 volt reference signal from the PCM, produced a linear analog voltage signal indicating atmospheric pressure.

BATT

Battery voltage.

Babbitt

An Alloy of tin, copper, and antimony having good anti friction properties used as a facing for bearings.

Backflushing

Pushing fluid in a direction opposite of normal flow. This is done for cleaning the engine's cooling system or fluid coolers and lines.

Backpressure

Pressure against which a fluid or gas is flowing, resulting from friction in lines, restrictions in pipes, valves, pressure in vessel to which fluid is flowing, hydrostatic head, or other impediment that causes resistance to fluid flow.

Banjo Fitting

A type of hydraulic fitting, shaped like a banjo, through which a hollow bolt passes, allowing fluid transfer from a hydraulic line to a hydraulic component

Battery Saver

The battery saver feature is a computer controlled feature that automatically turns off interior lights and come accessories in a parked vehicle after a few minutes to prevent the battery from being drained such as when a door is left ajar.

BDC - Bottom Dead Center

The lowest position of a piston during the stroke.

Bio-Diesel

The mono alkyl esters of long chain fatty acids derived from renewable lipid feedstocks, such as vegetable oils and animal fats, for use in compression ignition (diesel) engines. Manufactured by transestrification of the organic feedstock by methanol.

Blow-by

The passage of unburned fuel and combustion gases past the piston rings of internal combustion engines, resulting in fuel dilution and contamination of the crankcase oil.

Boost Pressure

1- The pressure of the charge air leaving a turbocharger or supercharger.
2- Inlet manifold pressure that is greater than atmospheric pressure.

Brake Horsepower (bhp)

The power output from an engine, not the indicated horsepower. The power output of an engine, sometimes called flywheel horsepower is less than the indicated horsepower by the amount of friction horsepower consumed in the engine.

Brake Horsepower (bhp) Net

Net brake horsepower is measured with all engine components. The power of an engine when configured as a fully equipped engine.

BTU - British thermal unit

The amount of heat required to raise the temperature of 1 pound of water 1 degree Fahrenheit

Bypass Filtration

A system of filtration in which only a portion of the total flow of a circulating fluid system passes through a filter at any instant or in which a filter having its own circulating pump operates in parallel to the main flow.

Cackle

A noise above the normal sound of combustion that may sound like a rod knock, but is intermittent and increases in intensity as the engine warms up to operating temperature. This noise is may be caused by a pressure variation within the fuel rail causing incomplete fuel fill in a fuel injector on split-shot injectors. The cackle is usually attributed to cylinder #8

CAC - Charge Air Cooling

A process of cooling the air coming from the turbocharger before it enters the engine

Calibration

The data values used by the strategy to solve equations and make decisions. Calibration values are stored in Read Only Memory and put into the processor during programming to allow the engine to operate within certain parameters

Calibration Oil

Oil which is used in a tester for checking injection nozzles and mechanical injection pumps, meeting SAE J967D specifications

Cam Follower

Also known as a "tappet" or a "lifter" this engine part contacts the lobes on a camshaft to change rotating motion to linear motion. Some cam followers are of solid construction but most modern engines use hydraulic cam followers that contain a hydraulic piston that uses engine oil under pressure to automatically adjust valve lash clearance

Camshaft

A shaft with eccentric lobes used in most internal combustion engines to open and close valves

Canister Style Oil Filter

An oil filter that requires only the element be replaced and not the housing

CAN

A communication protocol for data transfer between control modules

Carbon Dioxide (CO2)

A colorless, odorless, non-toxic gas. It is one of main products of fossil-fuel combustion. Carbon dioxide is a greenhouse gas that contributes to the potential for global warming

Carbon Monoxide (CO)

A colorless, odorless and toxic gas. It blocks the lungs’ ability to obtain oxygen. CO is produced by incomplete combustion of fossil fuels and is a major part of air pollution. Compression ignition (diesel) engines generate significantly lower CO emissions than spark ignited engines

Catalyst

A substance that causes a chemical reaction without undergoing a chemical change itself

Catalytic Converter

An anti-pollution device in the exhaust system that contains a catalyst for chemically converting some pollutants in the exhaust gasses into harmless compounds. (carbon monoxide, oxides of nitrogen and unburned hydrocarbons)

Cavitation

A dynamic condition in a fluid system that forms gas filled bubbles in the fluid

Cavitation Erosion

A material-damaging process which occurs as a result of vaporous cavitation. "Cavitation" refers to the occurrence or formation of gas- or vapor- filled pockets in flowing liquids due to the hydrodynamic generation of low pressure (below atmospheric pressure). This damage results from the hammering action when cavitation bubbles implode in the flow stream. Ultra-high pressures caused by the collapse of the vapor bubbles produce deformation, material failure and, finally, erosion of the surfaces

CCA - Cold Cranking Ampre Rating

A battery rating - The sustained constant current (in ampres) needed to produce a minimum terminal voltage under a load of 7.2 volts per battery after 30 seconds

Cetane Number

A measure of ignition quality of diesel fuel. The higher the cetane number the easier the fuel ignites when injected into an engine. Cetane number is determined by an engine test using two reference fuel blends of known cetane numbers. The reference fuels are prepared by blending normal cetane (n-hexadecane), having a value of 100, with heptamethyl nonane, having a value of 15

CKP Crankshaft Position Sensor

A magnetic pickup sensor that creates a sine wave voltage when the timing wheel on the crankshaft breaks its magnetic field. The CKP determines crankshaft position and speed

Charge Air

Dense, pressurized, heated air discharged from a turbocharger or supercharger

Clearance Volume

(of a cylinder) The space in the top of the cylinder into which the piston never intrudes. It is into this clearance volume that the charge air is compressed during an engine's compression stroke.

Closed Crankcase Breather

A ventilation system that recirculates crankcase vapors into the intake air system

Closed Loop Operation

In a system that uses sensors to provide feedback to the PCM, the PCM uses the sensor to continuously monitor variables and adjust to match engine requirements

Cloud Point

The temperature at which the paraffin in diesel fuel begins to form wax crystals making the fuel cloudy or hazy

CMP - Camshaft Position Sensor

A magnetic pickup sensor that creates a sine wave voltage when a peg on the camshaft breaks its magnetic field. The CMP determines which cycle the piston is in (compression or exhaust)

Coefficient of Friction

The number obtained by dividing the friction force resisting motion between two bodies by the normal force pressing the bodies together

Common Rail Injection

A diesel fuel injection system employing a common pressure accumulator, called the rail, which is mounted along the engine block. The rail is fed by a high pressure fuel pump. The injectors, which are fed from the common rail, are activated by solenoid valves. The solenoid valves and the fuel pump are electronically controlled. In the common rail injection system the injection pressure is independent from engine speed and load. Therefore, the injection parameters can be freely controlled. Usually a pilot injection is introduced, which allows for reductions in engine noise and NOx emissions

Compression Ignition

The form of ignition that initiates combustion in a diesel engine. The rapid compression of air within the cylinders generates the heat required to ignite the fuel as it is injected

Compression Ratio

The ratio between the volume of the cylinder and combustion chamber when the piston is at the bottom of its stroke, and the volume of the combustion chamber when the piston is at the top of its stroke

Connecting Rod

In a reciprocating piston engine, the connecting rod connects the piston to the crank or crankshaft. Together with the crank, they form a simple mechanism that converts linear motion into rotating motion

Continuous Monitor

A Powertrain Control module function that continuously monitors the inputs and outputs to ensure that readings are within set limits

Controller Area Network - CAN

A J1939 high speed communication link. CAN-1 is a public drive train data link between the vehicle modules and the PCM. CAN-2 is a private link between the PCM and the FICM/IDM

Coolant

A fluid used to remove and transfer heat

Crankcase

The housing that encloses the crankshaft, connecting rods and pistons. Other parts may also be housed in the crankcase depending on engine configuration

Crankcase Breather

A vent for the crankcase to release excess air pressure due to heat and combustion blow-by

Crankshaft

The part of an engine which translates reciprocating linear piston motion into rotary motion

CRH - Center Rotating Housing

The housing between the exhaust and intake sides of the turbo that houses the turbo shaft that houses the bearings, oiling system, and water-cooling system if equipped

Current

The flow of electrons flowing through a conductor (AMPS)

Damper

A device that reduces the amplitude of torsional vibration

Data Bus

The wiring which may be one or more circuits that connect the modules in a network to each other and diagnostic equipment

De-aeration

The removal or purging of gases entrapped in coolant or engine oil

De-aeration Tank / Degas Bottle

A separate tank in the cooling system used for one or more of the following functions:
1- De-aeration
2- Coolant reservoir (fluid expansion or afterboil)
3- Coolant retention
4- Filling
5- Fluid level indication

DEF - Diesel Exhaust Fluid

A urea-based chemical reactant designed specifically for use in SCR systems to reduce NOx emissions

Digital Fuel Injection

A fuel injection system that uses both an open and close signal to control fuel injectors

Dielectric Grease

A silicone based, electrically thermal insulating grease for use on wiring harnesses, bulkhead connectors, spark wires and other electrical connections. Prevents dirt, grease and moisture from contaminating connection and causing open circuits.

Diesel Particulate Filter (DPF)

An exhaust after treatment device that traps particulate matter, or soot, generated by the combustion process in diesel engines

Displacement

The stroke of the piston multiplied by the area of the cylinder bore multiplied by the number of cylinders in the engine. (Cubic inch - CID or cubic centimeter - CC)

DLC

Data Link Connector - An industry standardized 16-pin connector located below a vehicle's instrument panel that allows a technician to connect diagnostic equipment to perform tests, view data and program modules

Drive-By-Wire

One or more of the primary vehicle systems operate with electronic controls instead of a traditional mechanical linkage. An electronic signal transmits driver input to steering, throttle or brake input to an electronically controlled steering gear, throttle body or brake system

Driver

A transistor within an electronic module that controls power or ground to an actuator circuit

Downpipe

The exhaust pipe that leads from the turbo turbine outlet to the exhaust system under the vehicle

DTC

Diagnostic Trouble Code - Alpha-numeric codes generated by vehicle modules for troubleshooting vehicle operation. The codes may be generic in nature or manufacturer specific and identify a fault with a specific part, circuit or an operating condition.

Dual Timing System

A timing system that uses both a CKP and CMP sensors to determine engine speed and rotational position.

DVOM - Digital Volt Ohm Meter

A meter that uses a digital display to indicate a measured value. Preferred for use on microprocessor systems because a DVOM has a very high internal impedance and will not load down the circuit being measured

ECM - Electronic Control Module

An ECM controls one or more of the electrical subsystems in a vehicle. It receives electronic signals and commands, processes them and controls electrical output devices via a preset program

ECT - Engine Coolant Temperature Sensor

A thermistor style sensor used to indicate engine coolant temperature

EGR Cooler

A heat exchanger used to cool exhaust gases before they are returned to the intake air system

EGRV - Exhaust Gas Recirculation Valve

A valve used to control the flow of exhaust gases into the intake manifold

EGRP - Exhaust Gas Recirculation Valve Position Sensor

A potentiometer style sensor that indicates the amount of movement of the EGR valve

EGRT Outlet

EGR cooler outlet temperature sensor which is used aid in controlling EGR valve position and throttle position. This is a two wire thermistor type sensor - it's internal thermistor forms a voltage divider with a pullup resister inside of the ECM

EGT - Exhaust Gas Temperature

The temperature of the exhaust gasses leaving the engine measured in various points in the exhaust system. Monitoring exhaust temperature at the turbo indicates combustion temperatures. Monitoring exhaust gasses before and after the EGR coolers indicates EGR system operation and efficiency. Monitoring exhaust temperature in the aftertreatment system verifies DOC, DPF and SCR operation and helps prevent excessively high temperatures.

EOT - Engine Oil Temperature

A thermistor type sensor that indicates engine temperature

EP - Exhaust Pressure

The EP measures exhaust back pressure so that the ECM can control the EGR and turbocharger actuators. It is a three wire variable capacitance sensor. The ECM supplies a 5-volt reference signal which the EP sensor uses to produce a linear analog voltage to indicate pressure

ESP - Extended Service Plan

A Ford Motor Company Extended warranty and service contract. These contracts are sold by Ford, Lincoln and Mercury dealers

EVRT - Electronic Variable Response Turbocharger

The International Truck and Engine Corporation's trademark for its electronically-controlled turbo charger. Contains actuated vanes in the turbine housing that modify the flow characteristics of exhaust gasses through the turbine housing. The net benefit is the ability to provide the appropriate boost pressure for various engine speeds and load conditions. The EVRT lowers emissions and improves fuel economy. It also functions as a backpressure device which assists the EGR system and reduces engine warm up time

FEAD (belt)

FEAD or Front End Accessory Drive Belt is the drive belt on the front of an engine that drives the accessory equipment like power steering pumps, alternators and A/C compressors. This is also commonly referred to as the "serpentine" belt

FICM - Fuel Injection Control Module

An electronic unit which has the primary function of an electronic distributor for the injectors. It also is the power supply for the injectors

FMEM

Failure Mode Effects Management - A powertrain control module default operating mode that that allows the engine or transmission to function with limited capacity during a major system malfunction

FRP Fuel Rail Pressure

The FRP provides a feedback signal to the ECM indicating the fuel pressure at the fuel rail. It is a three wire variable capacitance sensor. The ECM supplies a 5-volt reference signal which the EP sensor uses to produce a linear analog voltage to indicate pressure

FTS Fuel Temperature Sensor

The FTS measures fuel temperature at the fuel rail and changes resistance according to changes in temperature. This is a two wire thermistor type sensor - it's internal thermistor forms a voltage divider with a pullup resister inside of the ECM. When the temperature of the fuel decreases, the resistance of the thermistor increases and the signal voltage increases. When the temperature of the fuel increases, the resistance of the thermistor decreases and the signal voltage decreases

Fuel Cooler

A heat exchanger that uses coolant to dissipate heat from the fuel before it is recirculated to the fuel system

Gage

An instrument or device for measuring, indicating or comparing a physical characteristic

GEM - Generic Electronic Module

The first body control module found in Ford trucks used to control body and chassis electronic features and tie together multiple systems such as lighting, power windows, power door locks, electronic four wheel drive systems and vehicle security

Glow Plug

A heating element that is mounted into the cylinder head of a diesel engine that heats the air in the combustion chamber and helps ignite fuel during cold starts and to help reduce white smoke emissions

Glow Plug Sleeves

Stainless steel sleeves used to protect the glow plugs from coolant

GPCM - Glow Plug Control Module

Module which supplies power to the glow plugs and identifies variation in current flow to the glow plugs. In trucks equipped with SCR systems the GPCM may also control the DEF tank heater

Hall Effect Sensor

A hall effect sensor generates a digital on/off signal that indicates engine speed and timing. The signal is created by a switching action caused by the passing of a vane though a positive and negative voltage potential. When the vane is between the potential, a signal is created. When the gap in between the potential is open, no signal is generated. The wider the vane the longer the duty cycle and the shorter the vane the shorter the duty cycle. A single shorter or longer vane can be used to identify position

Heat Exchanger

A device which transfers heat through a conducting wall from one fluid to another or from a fluid to air. Examples include radiators, condenser cores, oil coolers, after coolers

Heat Rejection

The process of heat transfer to the engine coolant

HFCM - Horizontal Fuel Conditioning Module

A frame mounted fuel conditioning module that contains an electric fuel pump, primary fuel filter and water separator with a water sensor

HPFP (High Pressure Fuel Pump)

A fuel pump that creates and maintains a high pressure fuel supply used on a common rail fuel injection system

Hydrocarbons - Hc

Compounds containing only carbon and hydrogen. Petroleum consists chiefly of hydrocarbons

Hydraulic/Electronic Unit Injector (HEUI)

A type of unit injector actuated by engine oil pressure rather than the camshaft. A very high oil pressure (up to 3,000 psi) is created by a separate oil pump. This high pressure is routed to every injector through a gallery. The engine’s Electronic Control Module varies the pressure in response to engine speed and other parameters

Hydrometer

An instrument for determining either the specific gravity of a liquid or the API gravity

IAT - Intake Air Temperature Sensor

A thermistor style sensor used to indicate air temperature before the charge air cooler

IAT2 - Intake Air Temperature 2 Sensor

A thermistor style sensor used to indicate air temperature - after passing through the charge air cooler

In-line Filter

A filter assembly in which the inlet, outlet and filter element axes are in a straight line

ICP- Injection Control Pressure

A variable capacitance style sensor used to indicate high pressure oil system pressure

IDM - Injector Drive Module

An electric unit which has a primary function of an electronic distributor for the injectors. It also is the power supply for the injectors. It supplies 90 volts at 7 amps to the injectors

IDS - Integrated Diagnostic System

The current modular diagnostic system to support the latest Ford vehicles that uses a PC or laptop , IDS Software, a Vehicle Communication Module (VCM) to interface with vehicle modules, a Vehicle Measurement Module (VMM) to perform specialized electrical tests.

Impedance

A form of opposition to AC current flow measured in Ohms

Impeller

Another name for a turbocharger compressor wheel.

Inhibitor

Any substance that slows or prevents such chemical reactions as corrosion or oxidation

I/0 Injector Test

A test that can be performed using the WDS to disable one injector at a time while watching Mfdes to determine a weak contributing injector

IPR - Injection Pressure Regulator

Controls injection oil pressure. An electrical signal to a solenoid creates a magnetic field which applies a variable force on a poppet to control pressure. The quantity of fuel delivered to the combustion chamber is proportional to injection control pressure

ISO

International Standards Organization 9140 protocol

IVS - Idle Validation Switch

An on/off switch that indicates when the accelerator pedal is in the idle position

J1850

A network protocol also referred to as Standard Corporate Protocol or SCP

Journal

Part of a shaft or axle in contact with, or enclosed by, a bearing.

KAM - Keep Alive Memory

A portion of the memory within the PCM that must have power even when the vehicle is not operating

KAPWR - Keep Alive Power

A dedicated and unswitched power circuit that maintains KAM

KOEO - Key On Engine Off Self Test

A self-test operation that is performed with the ignition switch in the ON position with the engine OFF

KOER - Key On Engine Running Self Test

A self-test operation that is performed with the ignition switch in the ON position and the engine RUNNING

KPWR

Battery voltage that is received indicating that the ignition switch is in the ON position

Lubricant

Any substance interposed between two surfaces in relative motion for the purpose of reducing the friction and/or the wear between them

Lubricity

The ability of an oil, fluid or grease to lubricate; also called film strength

LONGFT1, LONGFT2 = Long-Term Fuel Trim

Fuel flow adjustment determined by the PCM

LOOP

Indicates OPEN or CLOSED loop status

LSD - Low Sulfur Diesel

Low sulfur diesel is diesel fuel that has been refined so that its sulfur content is 500 parts per million (ppm) or less.

Main Power Relays

Battery power relay switches for the PCM and FICM (modules) that are key power initiated and controlled by the corresponding powered module

MAP - Manifold Absolute Pressure Sensor

A MAP sensor generates a digital frequency that indicates manifold boost pressure above atmospheric pressure. The signal is created by switching action caused by manifold pressure of a diaphragm connected to a capacitor circuit in the sensor. The digital frequency increases as pressure increases. A MAP sensor has three connection: signal return(gnd), MAP signal, and VREF

Misfire Detection

Uses engine RPM changes during a firing cycle to determine a low contributing cylinder

Modular Water Pump

Is a water pump that uses the front cover as a housing and only the hub and impeller are replaceable

Multiplexing

A method by which multiple digital data streams are combined into one signal over a shared network of modules. This strategy allows control modules to communicate during normal vehicle operation.

NA - Naturally Aspirated

An engine that is not supercharged or turbocharged. Air is induced by the force of natural air pressure

Network

The control modules and wiring that allow data to be sent or received. A network may be directly wired or wireless.

Normally Closed

Refers to a switch or a solenoid that is closed when no control or force is acting on it

Normally Open

Refers to a switch or a solenoid that is open when no control or force is acting on it

Nitrogen Oxides (NOx)

Several air-polluting gases composed of nitrogen and oxygen which play an important role in the formation of photochemical smog. Nitrogen oxides are collectively referred to as ”NOx”, where ”x” represents a changing proportion of oxygen to nitrogen. Internal combustion engines are significant contributors to the worldwide nitrogen oxide emissions. For the purpose of emission regulations, NOx is composed of colorless nitric oxide (NO), and the reddish-brown, very toxic and reactive nitrogen dioxide (NO2). Other nitrogen oxides, such as nitrous oxide N2O (the anesthetic ”laughing gas”), are not regulated emissions

NOx Sensor

Mounted in the exhaust system the NOx sensor monitors the amount of N0x in the exhaust stream. The information from this sensor is used to adjust the amount of DEF being injected, adjust fuel trim and monitor the efficiency of the SCR system.

OASIS - Online Automotive Information System

A computer system that provides vehicle, warranty, recall,and ESP information about specific vehicles. OASIS is accessible by authorized Ford and Ford dealer employees using computer terminals at the dealership and at Ford Motor Company

Oil Cooler

A heat exchanger that uses engine coolant to dissipate heat from the engine oil

On-Board Diagnostics (OBD)

A system on board of the vehicle that monitors emission control components and alerts the driver (e.g., by a dashboard light) if malfunctions or emission deterioration occurs. The OBD system involves a number of sensors and a data processor, which is typically integrated with the vehicle's electronic management system

Open Loop - OL

An operating condition based on instructions not modified by PCM feedback

Oxidation Catalytic converter - OC

A catalytic converter system that reduces the levels of HC and CO emissions

Oxygen Sensor - O2S

Provides information on rich or lean exhaust conditions to the PCM

Particulate Matter - PM

Particles formed by incomplete combustion of fuel. Compression ignition (diesel) engines generate significantly higher PM emissions than spark ignited engines. The particles are composed of elemental carbon, heavy hydrocarbons (SOF), and hydrated sulfuric acid (sulfate particulates)

PATS - Passive Anti-Theft System

A vehicle security system that prevents engine operation if a theft attempt is detected. It protects against theft by requiring a specially coded ignition key that transmits a unique code to the vehicles computers. The vehicle starts and operates only with the key that matches the key code programmed to the vehicle

PCM - Powertrain Control Module

The housing that contains the micro computer, VREF regulator, input conditioners and output drivers

PCV - Pressure Control Valve

A fuel control valve permanently attached to the high pressure fuel pump in a 6.4L PSD engine. The PCV governs the fuel pressure that is delivered to the fuel injectors and acts as a dampening device for the fluctuations in pressure that occur during fuel delivery through the pump and the injection process

PDS - Portable Diagnostic Software

Pinpoint Test

A diagnostic test found in the workshop manual that helps diagnose the cause of a DTC or vehicle concern

Piston

In an engine, its purpose is to transfer force from expanding gasses in the cylinder to the crankshaft via a connecting rod

Piston Cooling Jets

Mounted inside the engine block under each cylinder the cooling jets spray engine oil into a hole at the bottom of the pistons to cool the top of the pistons

Potentiometer

Converts a mechanical motion to a voltage value. Most often used to sense the position of a component. This sensor works as a variable voltage divider. The wiper arm is mechanically connected to the component desired to be sensed. Potentiometers have three connections: VREF, signal out, and ground

Pour Point

A measure of the ability of a diesel fuel to operate under cold weather conditions. Defined as the temperature at which the amount of wax out of solution is sufficient to gel the fuel when tested under standard conditions (ASTM D97)

Pre combustion Chamber

A small, auxiliary combustion chamber connected by a narrow orifice with the main chamber. Fuel is injected into the pre chamber and ignites there, causing hot gases to expand into the main chamber (cylinder)

Protocol

The electronic language that network modules use to communicate

Pulse Width

The length of time an actuator, such as an injector, remains energized

Pushrod

A metal rod that transmits reciprocating motion from a camshaft to the valves of an internal combustion engine having the camshaft in the crankcase

There are no terms that start with this letter.

RAM - Random Access Memory

Memory into which information can be written as well as read

Reductant

Also known as diesel exhaust fluid is 32.5% urea and water

Relative Compression Test

A test that can be run with the Ford scan tool to measure compression of a cylinder relative to the other cylinders in the engine. This test is accomplished by comparing the rpm of the engine during each compression stroke

Regeneration

As related to diesel particulate filters, regeneration is the process of burning off accumulated soot that is trapped and stores. This process restores efficiency of the filter

Relay

An electromechanical device in which connections in one circuit are opened or closed by changes in another circuit

RFI

Radio Frequency Interference

Rocker Arm

A reciprocating lever that conveys radial movement from the cam lobe into linear movement at the poppet valve to open it. One end is raised and lowered by the rotating lobes of the camshaft (either directly or via a tappet (lifter) and pushrod) while the other end acts on the valve stem

Rocker Arm Carrier

A housing that the rocker arms and their fulcrums are mounted to

ROM = Read-Only Memory

Computer memory that can be accessed and used, but not altered

Runaway

Diesel engine which fails to respond to the usual controls and continues to accelerate after reaching its safe maximum speed, with consequent risk of major damage or disintegration. Even after the normal fuel supply is shut off the engine may continue to run, fuelled by lubricating oil vapor drawn past the piston rings from the crankcase, turbocharger or pooled oil in the intake system

SBDS - Service Bay Diagnostic System

A computer based diagnostic system that allows access to network that can perform self tests, monitor and record parameter data, program modules and can activate control module outputs. Tis service tool was retired in the early 1990's and replaced with the WDS diagnostic tool.

SCP - Standard Corporate Protocol

SCR - Selective Catalytic Reduction

A means of converting nitrogen oxides, also referred to as NOx with the aid of a catalyst into diatomic nitrogen, N2, and water, H2O

SEIC

Stationary Elevated Engine Idle Control is a powertrain control module (PCM) strategy that provides elevated engine speed to drive auxiliary commercial equipment such as hydraulic pumps, generators, air compressors or maintain vehicle battery charge.

Shield

A conducting sleeve that surrounds wires to be electronically isolated from electromagnetic interference (EMI)

SIG RTN - Signal Return

A dedicated sensor ground circuit that is common to 2 or more sensors

Split Shot Injector

Split Shot Injectors provide improved exhaust emissions and quiets engine operation by tailoring the injection of fuel, without a decrease in performance

SSCC

"Symptom to System to Component to Cause" is a diagnostic strategy that allows a technician to diagnose vehicle concerns in a logical sequence

Stiction

A term based on the blending of "static friction" perhaps also influenced by the verb "stick." Two solid objects pressing against each other (but not sliding) will require some threshold of force parallel to the surface of contact in order to overcome static cohesion. Stiction is a threshold, not a continuous force. As applied to our profession, the spool valves in certain fuel injectors can stick due to the viscosity of the engine oil coating them. This can cause a spool valve to stick or operate in a delayed or slow motion causing driveability issues

Stoichiometry

An air/fuel mixture that is neither too rich nor too lean. Stoichiometric ratio is 14.7 parts of air for every 1 part of fuel

Sulfur

A pale-yellow, brittle nonmetallic element that occurs widely in nature, especially in volcanic deposits, minerals, natural gas, and petroleum. It is used to make gunpowder and fertilizer, to vulcanize rubber, and to produce sulfuric acid. Sulfur is a natural part of the crude oil from which diesel fuel is derived, is one of the key causes of particulates or soot in diesel.

Symptom Chart

A chart found in the workshop manual that uses symptom descriptions to direct technicians to specific diagnostic tests or diagnostic routines

Thermistor

Sensor used to determine temperature. A thermistor changes it's resistance value in relation to temperature change. Increasing temperature results in decreasing resistance, decreasing temperature results in increasing resistance. The thermistor in conjunction with a current limiting resistor in the PCM forms a voltage divider that provides a voltage signal indicating temperature. Since the top half of the voltage divider is the current limiting resistor and is internal to the PCM, a thermistor sensor only has two connections, signal return and ground

TPMS (Tire Pressure Monitoring System)

A tire pressure monitoring system (TPMS) is an electronic system to monitor the air pressure inside a pneumatic tire. They are sometimes referred to as remote tire pressure monitoring systems (RTPMS) or simply as run flat indicators. This system is required on all light motor vehicles under 10,000 lbs sold after September 1, 2007. For more information Google "TREAD Act."

Turbine Wheel

The finned wheel on the exhaust side of a turbocharger that is propelled by the exhaust gasses leaving the engine

Turbocharging

A process of compressing the engine intake air charge in order to allow more air and fuel into the cylinder and, thus, to increase the engine power output. The compressor, called the turbo charger, is driven by an exhaust gas propelled turbine

Turbo Lag

The time delay between injecting fuel to accelerate and delivering air to the intake manifold by the turbocharger. This phenomenon may cause black smoke emissions in some turbocharged diesel engines during acceleration

ULSD - Ultra Low Sulfur Diesel

Ultra low sulfur diesel is diesel fuel that has been refined so that its sulfur content is 15 parts per million (ppm) or less.

UVCH - Under Valve Cover Harness

The injector wiring for the fuel injectors located under the valve covers of Power Stroke engines

Variable Capacitance Sensor

A sensor that is used to determine pressure. A variable capacitance sensor changes it capacitance value in relation to pressure change. Increasing pressure results in a lower capacitance, thus increasing return voltage. Decreasing pressure results in a higher capacitance and a lower voltage. Variable capacitance sensors are 3 wire sensors

VCM - Vehicle Communication Module

A vehicle serial communications gateway that provides multiple vehicle serial communication interfaces that allow scan tools and computers to communicate with Ford Motor Company vehicles. The VCM is used with the Ford WDS, NGS, and IDS diagnostic scan tools

VCV - Volume Control Valve

A control valve permanently attached to the high pressure fuel pump in a 6.4L PSD engine. The VCV regulates the delivery of fuel from the internal transfer pump to the high pressure pumping elements and adjusts the low pressure side of the system to match the needs of the engine thus increasing efficiency

VGT - Variable Geometry Turbocharger

A turbocharger that has a turbine housing that can change sizes through electronically controlled hydraulics

VGTCV - Variable Geometry Turbocharger Control Valve

Could also be called EVRTCV. Controls oil flow in and out of the VGT actuator in order to change the effective size of its turbine housing

Visctronic Fan Clutch

A viscous cooling fan clutch that employs an electronically controlled clutch. The fan drive is controlled by the engine's control module for precise fan speed modulation.

VPWR

Battery voltage

VREF

5 volt reference voltage generated by the PCM

VMM - Vehicle Measurement Module

The hardware and cables that provide instrumentation to the IDS. It's functionality includes ignition system tests, fuel pressure tests, fuel leak-down tests, injector flow test, secondary ignition, current probe functionality, oscilloscope, digital multi-meter, pressure and vacuum gauge and variable geometry turbocharger functional tests

VSS - Vehicle Speed Sensor

Normally a magnetic pickup style sensor that is mounted on the tailshaft of the transmission to indicate ground speed

WABAC

The WABAC Machine (pronounced, and often synonymous with, Wayback) refers to a fictional machine from the cartoon segment Peabody's Improbable History, an ongoing feature of the 1960's cartoon series The Rocky and Bullwinkle Show. The WABAC Machine is a plot device used to transport the characters Mr. Peabody and Sherman back in time. The meaning of the acronym is unknown, but mid-century, big-science project names, such as ENIAC and JOHNNIAC, often ended in "AC".

Wastegate

A device used on turbochargers to limit boost production by bleeding exhaust gasses and pressure to slow the turbine and compressor wheels. It can allow increased boost pressures in the air charging system at low speeds while not hindering top end performance

WDS - World Diagnostic System

There are no terms that start with this letter.

There are no terms that start with this letter.

There are no terms that start with this letter.