Terminology Glossary
WARNING: This page is about a different car, the 2001 Jaguar XKR and 2001 Jaguar XK8. However, it is still accessible from the selected car via links, so may be relevant.
This glossary of terms is intended to cover emissions-related (to SAE J 1930) terminology, and other abbreviations that may be used in this service information.
The required term may be looked-up in the left-hand column, and subsequent columns give the standard acronym, unit or abbreviation, and definition.
TERMINOLOGY GLOSSARY
| Term(s) | Acronym / Unit / Abbreviation | Definition |
|---|---|---|
| A | ||
| Accelerator Pedal | AP | |
| After Bottom Dead Center | ABDC | Event occurring after BDC |
| After Top Dead Center | ATDC | Event occurring after TDC |
| Airbag / Supplementary Restraint System | Airbag, SRS | Airbag restraint system for driver and front seat passenger |
| Air Cleaner | ACL | |
| Air Conditioning | A/C | |
| Air Conditioning Control Module | A/CCM | Module controlling air conditioning, heating and ventilation |
| Air Conditioning Signal | ACS | Air conditioning compressor clutch operation is signalled to the ECM which induces idle speed corrections to compensate for engine load changes |
| Alternating current | ac | |
| Air Fuel Ratio | AFR | Nominally 14.7 parts air to one part fuel |
| Ampere | A | SI unit of current |
| Ampere hour | Ah | A current of one ampere flowing for one hour |
| Anti-Lock Braking System | ABS | System which prevents wheel lock-up under braking by sensing lack of rotation of a wheel(s) and diverting fluid pressure away from it (them) |
| ABS Control Module | ABS CM | |
| ABS / Traction Control Control Module | ABS / TC CM | |
| Atmosphere | atm | Unit of pressure (1.01325 bar) |
| Automatic Stability Control | ASC | A form of vehicle control in which the ECM reduces engine torque to control wheel-spin |
| B | ||
| Barometric Absolute Pressure Sensor | BARO | Sensor measuring the pressure of surrounding air at any given temperature and altitude |
| Battery positive voltage | B+ | The positive voltage from a battery or any circuit connected directly to it |
| Before Bottom Dead Center | BBDC | Event occurring before BDC |
| Before Top Dead Center | BTDC | Event (usually ignition) occurring before TDC |
| Blower | BLR | Device which supplies a current of air at moderate pressure, e.g. heater or A/C blower |
| Body Processor Module | BPM | Control module for body electrical systems, e.g. interior lamps, windshield wash / wipe control |
| Bottom Dead Center | BDC | Lowest point of piston travel in a reciprocating engine |
| Brake horsepower | bhp | Effective horsepower developed by an engine or motor, as measured by a brake applied to its output shaft |
| Brake Mean Effective Pressure | BMEP | That part of the effective pressure developed in a cylinder that would result in a cylinder output equal to the bhp of the engine |
| Brake On/Off | BOO | Indicates the position of the brake pedal |
| British Standard | BS | Standard specification issued by the British Standards Institution |
| British Standard Automotive | BSAu | |
| Bus | Topology of a communication network | |
| Bypass Air | BPA | Mechanical control of throttle bypass air |
| C | ||
| Camshaft Position Sensor | CMPS | Indicates camshaft position |
| Canadian Motor Vehicle Safety Standard | CMVSS | |
| Canister Purge | CANP | Controls purging of the EVAP canister |
| Carbon dioxide | CO2 | Colorless gas with a density of approximately 1.5 times that of air |
| Carbon monoxide | CO | Poisonous gas produced as the result of incomplete combustion |
| Case Ground | CSE GND | Control module casing ground |
| Catalytic converter | In-line exhaust system device used to reduce the level of engine exhaust emissions | |
| Celsius | C | SI term for the Centigrade scale, with freezing point at zero and boiling point at 100° |
| Central Processor Unit | CPU | The section of a computer that contains the arithmetic, logic and control circuits. It performs arithmetic operations, controls instruction processing, and provides timing signals and other housekeeping operations |
| Closed Loop | CL | |
| Closed Loop System | CLS | Control system with one or more feedback loops |
| Column/Mirror Control Module | C/MCM | |
| Control Module | CM | A self-contained group of electrical/electronic components, designed as a single replaceable unit, and controlling one or more processes |
| Controller Area Network | CAN | A communication system which allows control modules to be linked together in a network. |
| Crankshaft Position Sensor | CKPS | Generates crankshaft position information in conjunction with the CKPTR (also generates speed information in certain applications) |
| Crankshaft Position Timing Ring | CKPTR | Toothed ring which triggers the CKPS |
| Crankcase Ventilation System | CV | System which scavenges camshaft cover and crankcase emissions and feeds them into the inlet manifold |
| Cubic centimeter | cm3 | |
| Curb weight | Weight of vehicle with fuel, lubricants and coolant, but excluding driver, passengers or payload | |
| D | ||
| Data Link Connector | DLC | Connector providing access and/or control of the vehicle information, operating conditions, and diagnostic information |
| Degree | deg, ° | Angle or temperature |
| Department of Transport (US) | DOT | |
| Department of Transport (UK) | DTp | |
| Deutsche Institut fur Normung | DIN | German standards regulation body |
| Diagnostic Module | DM | Supplemental Restraint System (non-controlling) module for diagnostics overview |
| Diagnostic Test Mode | DTM | A level of capability in an OBD system. May include different functional states to observe signals, a base level to read DTCs, a monitor level which includes information on signal levels, bi-directional control with on/off board aids, and the ability to interface with remote diagnosis |
| Diagnostic Trouble Code | DTC | An alpha/numeric identifier for a fault condition identified by the On-Board Diagnostic (OBD) system |
| Dial test indicator | DTI | |
| Differential pressure | pressure difference btween two regions e.g. between intake manifold and atmospheric pressures | |
| Differential pressure feedback EGR | DPFE | An EGR system that monitors differential EGR pressure across a remote orifice to control EGR flow |
| Direct current | dc | Current which flows in one direction only, though it may have appreciable pulsations in its magnitude |
| Dual linear switch | DLS | J-gate switch connected to the TCM on SC vehicles |
| E | ||
| EGR Temperature EGRT Sensor | EGRT | Sensing EGR function based on temperature change |
| EGR Vacuum Regulator | EVR | Controls EGR flow by changing vacuum to the EGR valve |
| EGR Valve Position | EVP | An EGR system that directly monitors EGR valve position to control EGR flow |
| Electrically Erasable Programmable Read-Only Memory | EEPROM | |
| Electrically Programmable Read-Only memory | EPROM | |
| Electronic Secondary Air Injection | EAIR | A pump-driven system for providing secondary air using an electric air pump |
| Engine Control Module | ECM | |
| End of dash | EOD | Referring to a vehicle fascia, eg EOD air vent |
| Engine Coolant Level | ECL | |
| Engine Coolant Temperature | ECT | |
| ECT Sensor | ECTS | Thermistor which provides engine coolant temperature signal to the ECM to trigger enrichment circuits which increase injector 'on' time for cold start and warm-up |
| Engine speed | RPM | |
| Environmental Protection Agency | EPA | |
| Evaporative Emission | EVAP | System designed to prevent fuel vapor from escaping into the atmosphere. Typically includes a charcoal filled canister to absorb fuel vapor |
| Evaporative Emission Control Valve | EVAPP | |
| Exhaust Gas Recirculation | EGR | System which reduces NOx emissions by adding exhaust gases to the incoming fuel/air charge |
| Exhaust Gas Recirculation Solenoid Vacuum Valve | EGRS | |
| Exhaust Gas Recirculation Temperature Sensor | EGRT Sensor | |
| Exhaust Gas Recirculation Valve | EGRV | |
| F | ||
| Fan Control | FC | Engine cooling fan control |
| Federal Motor Vehicle Safety Standard (US) | FMVSS | |
| Figure | Fig. | Illustration reference |
| Flash Electrically Erasable Programmable Read-Only Memory | FEEPROM | |
| Flash Erasable Programmable Read-Only Memory | FEPROM | |
| Flywheel Sensor | CKFS | Sensor mounted so as to be triggered by each flywheel ring gear tooth to give an engine speed signal |
| Fuel Injectors | FI | Solenoid operated devices that spray a metered quantity of fuel into the inlet ports |
| Fuel Pressure Regulator Control | FPRC | Controls fuel pressure regulator; used primarily to give extra fuel at cold start-up |
| Fuel Pump | FP | |
| Fuel Pump Monitor | FPM | Monitors operation of fuel pump |
| Fuel Pump Relay | FPR | |
| Fuel rich/lean | Qualitative evaluation of air/fuel ratio based on a ratio known as stoichiometry, or 14.7:1 (Lambda) | |
| Full Scale Deflection | FSD | The maximum indication point on an analogue meter or gauge |
| G | ||
| Generator | GEN | Rotating machine which converts mechanical energy into electrical energy |
| Gramme centimeter | gcm | |
| Gramme (force) | gf | |
| Gramme (mass) | g | |
| Ground | GND | Electrical conductor used as a common return for an electrical circuit or circuits, and with a relative zero potential |
| H | ||
| Hard fault | A fault currently present in the system | |
| Headlamp | HL | |
| Heated Oxygen Sensor | HO2S | Electrically heated oxygen sensor which induces fueling corrections |
| Hertz (frequency) | Hz | Frequency, one cycle per second |
| High Mounted Stoplamp | HMSL | |
| High tension (electrical) | ht | |
| Hour | h | |
| Hydrocarbon | HC | |
| I | ||
| Idle Air Control | IAC | Electrical control of throttle bypass air |
| Idle Air Control Valve | IACV | Stepper motor driven device which varies the volume of air by-passing the throttle to maintain the programmed idle speed |
| Ignition | ign | |
| Ignition amplifier | IA | Device which amplifies the ignition system output |
| Ignition ground | IGN GND | |
| Inertia Fuel Shut-off | IFS | An inertia system that shuts off the fuel supply when activated by pre-determined force limits brought about by (e.g.) collision |
| Inertia Fuel Shut-off Switch | IFSS | Shuts down fuel and ignition systems in the event of a vehicle impact |
| Intake air | Air drawn through a cleaner and distributed to each cylinder for use in combustion | |
| Input | I/P | An electrical input signal to a controlling device |
| Intake Air Temperature | IAT | Temperature of intake air |
| Intake Air Temperature Sensor | IATS | Device used to measure IAT |
| Intake Air Temperature Sensor Ignition | IATSI | Thermistor which signals the ECM to retard the ignition timing in response to high inlet air temperatures |
| Intake Air Temperature Sensor Injection | IATSF | Thermistor which inputs air density information to the ECM |
| Internal diameter | i.dia | |
| International Standards Organization | ISO | |
| J | ||
| K | ||
| Kilogramme (mass) | kg | |
| Kilogramme (force) | kgf | |
| Kilogramme force per square centimeter | kgf/cm2 | |
| Kilometer | km | |
| Kilometer per hour | km/h | |
| Kilopascal | kPa | |
| Kilovolt | kV | |
| Knock Sensor | KS | Sensor which detects the onset of detonation, and signals the ECM to retard the ignition |
| L | ||
| Left-hand | LH | |
| Left-hand drive vehicle | LHD | |
| Left-hand thread | LH Thd | |
| Light Emitting Diode | LED | Light-emitting semiconductor diode used in alphanumeric displays and as an indicator lamp |
| Liquid Crystal Display | LCD | Optical digital display system, applied voltage to which varies the way the crystals reflect light, thereby modifying the display |
| Liter | L | |
| Low tension | It | Primary circuit of the ignition system, linking the battery to the primary winding in the ignition coil |
| M | ||
| Malfunction Indicator Lamp | MIL | A required on-board indicator to alert the driver of an emission related malfunction |
| Manifold Absolute Pressure | MAP | Absolute pressure of the intake manifold air |
| Manifold Absolute Pressure Sensor | MAPS | Sensor located in the ECM and ported to the intake manifold |
| Manifold Surface Temperature | MST | |
| Mass Air Flow | MAF | System which provides information on the mass flow rate of the intake air to the engine |
| Mass Air Flow Sensor | MAFS | Hot-wire sensor which monitors air flow into the intake manifold for fueling and ignition control |
| Maximum | max. | |
| Meter (measurement) | m | |
| Metric (screw thread, e.g. M8) | M | |
| Microfarad | MFD | Unit of electrical capacitance, one millionth of a farad |
| Millimeter | mm | |
| Millimeter of mercury | mmHg | |
| Millisecond | ms | |
| Minimum | min. | |
| Minute | minute | |
| Model Year | MY | |
| Module | M | Self contained group of electrical/electronic components which is designed as a single replaceable unit |
| Modulating signal | MD | A shift process signal to the TCM on SC vehicles |
| Motorized In-Car Aspirator | MIA | Device which constantly samples cabin temperature by passing air over a sensor, and communicates with the A/CCM to modify A/C system performance to suit |
| Multi Protocol Adaptor | MPA | An interpreter for the various data languages present on a vehicle |
| N | ||
| National Institute of Occupational Safety and Health (US) | NIOSH | |
| Newton | N | SI unit of force. 1 N = 0.2248 pounds force |
| Newton meter | Nm | SI unit of torque. Must not be confused with nm (nanometer) |
| Nitrous Oxide | NOx | Compounds of nitrogen and oxygen formed at high temperatures. Major source of exhaust-gas air pollution |
| Non-Volatile Random Access Memory | NVRAM | RAM which retains memory even if power supply is interrupted |
| Normally aspirated | Fueling system using intake air at atmospheric pressure; not supercharged or turbocharged | |
| Normally Closed | NC | |
| Normally Open | NO | |
| North American Specification | NAS | Vehicles for sale in the USA and Canadian markets |
| Number | No. | |
| O | ||
| Occupational Safety and Health Administration (US) | OSHA | |
| On-Board Diagnostic | OBD | A system that monitors some or all computer input and output control signals. Signal(s) outside the pre-determined limits imply a fault in the system or a related system |
| On-Board Refueling Vapor Recovery | ORVR | |
| Original Equipment Manufacturer | OEM | |
| Output | O/P | An electrical output signal from a controlling device |
| Outside diameter | o. dia | |
| Oxides of nitrogen | NOx | |
| Oxygen sensor | O2S | A sensor which detects oxygen content in the exhaust gases |
| P | ||
| Parameter Identifier | PID | An index number referring to a parameter within a module without knowledge of its storage location |
| Park Neutral Position | PNP | |
| Park Neutral Position Switch | PNPS | Indicates the selected non-drive modes of the (automatic) transmission |
| Part number | part no. | |
| Portable Diagnostic Unit | PDU | Comprehensive electrical diagnosis system specific to Jaguar vehicles |
| Position | pos'n | |
| Power Assisted Steering | PAS | Hydraulic pump-assisted steering system |
| Power Steering Pressure | PSP | |
| Programmable Electronic Control Units System | PECUS | Process whereby a common ECM is programmed on the production line to suit the market requirements of a particular vehicle |
| Programmable Read-Only Memory | PROM | ROM with some provision for setting the stored data after manufacture |
| Pulse Width Modulation | PWM | A method of control in an electronic control system in which the duration of pulses in a pulse train is proportional to the amplitude of the modulating signal |
| Q | ||
| R | ||
| Random Access Memory | RAM | Fast access memory store which is accessible for entry or extraction of data |
| Read-Only Memory | ROM | Fast access memory in which data is fixed and may not be changed |
| Reservoir | RES | Container, usually for oils, coolants or hydraulic fluids |
| Return | RTN | A dedicated sensor ground circuit |
| Revolutions Per Minute | RPM | Shaft speed of a device, usually an engine or motor |
| Right-hand | RH | |
| Right-hand drive vehicle | RHD | |
| S | ||
| Scan Tool | ST | Device that interfaces with and communicates information on a data link |
| Seat Control Module | SCM | Module controlling the seat motor systems (not electric raise/lower-only seats) |
| Secondary Air | Air provided to the exhaust system | |
| Secondary Air Injection | AIR | System used for a period of time each time the engine is started, unless certain temperature criteria are met. Pumps air directly into the exhaust system which generates extra heat and reduces the time taken for the catalytic converters to reach operating temperature |
| Secondary Air Injection Bypass | AIRB | Vents secondary air to atmosphere |
| Secondary Air Injection Check Valve | AIRC | Valve which prevents back-flow of exhaust gas to the AIR system when the system is inoperative |
| Secondary Air Injection Diverter | AIRD | Diverts secondary air to either the catalyst or exhaust manifold |
| Secondary Air Injection Magnetic Clutch | AIRPC | Clutch mounted on the AIRP drive shaft |
| Secondary Air Injection Pump | AIRP | Mechanically driven rotary vane pump, driven through the AIRPC |
| Secondary Air Injection Relay | AIRR | Controls the injection of air into the exhaust system |
| Secondary Air Injection Switching Valve | AIRS | Vacuum operated valve backing-up the AIRC |
| Security and Locking Control Module | SLCM | Module controlling the vehicle's security and closure-locking functions |
| Sensor | S | Generic name for a device that senses either the absolute value or a change in a physical quantity such as temperature, pressure or flow rate, and converts that change into an electrical quantity signal |
| Service Repair Operation (number) | SRO | Number generated by Jaguar Methods and Techniques system which relates to the time allowed to complete a repair operation. Further information on the system can be found in the separate Jaguar Publications (for each model range) entitled 'Repair Operation Times' |
| Shift signal | SD | A shift process signal to the TCM on SC vehicles |
| Shift Solenoid | SS | Controls shifting in an automatic transmission |
| Signal return | SIG RTN | |
| Sliding Roof Control Module | SRCM | |
| Society of Automotive Engineers | SAE | |
| Speed Control Control Module | SCCM | Module controlling Speed Control System |
| Square centimeter | cm2 | |
| Standard | std | |
| Standard Corporate Protocol | SCP | A high-speed, serial communications system linking all body system control modules. Control messages and data are passed between modules at up to 786 messages per second |
| Supercharger | SC | An intake system which utilizes a supercharger (mechanically driven device that pressurizes intake air, thereby increasing density of charge air and the consequent power output from a given displacement) |
| Supercharger Bypass | SCB | |
| Switch | SW | |
| T | ||
| Tachometer | TACH | A circuit that provides input for an electronic tachometer display |
| Thermal Vacuum Valve | TW | Controls vacuum levels or routing based on temperature |
| Throttle Body | TB | Device containing the throttle |
| Throttle Position | TP | |
| Throttle Position Sensor | TPS | Interprets throttle position and movement to identify idle, acceleration and full-power demands |
| Top Dead Center | TDC | |
| Torque Converter Clutch | TCC | |
| Total indicator reading | TIR | The total indicated movement on a DTI with the test piece rotated through 360° |
| Transmission Control Module | TCM | Controls the shifting pattern of the (automatic) transmission |
| Transmission Control Switch | TCS | Modifies the operation of electronically controlled transmissions |
| Transmission Oil Temperature | TOT | Indicates temperature of transmission fluid |
| Transmission Range | TR | The range in which the transmission is operating |
| Transmission Speed Sensor | TSS | Indicates rotational speed of transmission output shaft or turbine shaft |
| V | ||
| Vacuum Solenoid Valve | VSV | Vacuum operated valve used in the speed control system |
| Vacuum Solenoid Valve (atm) | VSV VA | Vacuum atmospheric valve used in the speed control system |
| Vacuum Solenoid Valve (rel) | VSV VR | Vacuum release valve used in the speed control system |
| Vacuum Solenoid Valve (vac) | VSV VV | Vacuum valve used in the speed control system |
| Variable Valve Timing | VVT | A system by which the relationship of the crankshaft and camshaft may be altered during engine running |
| Vehicle Battery Adapter | VBA | Provides electrical power to the PDU and supplies a battery reference level |
| Vehicle Condition Monitor | VCM | Instrument panel display which warns of faults |
| Vehicle Emission Control Information Label | VECI Label | |
| Vehicle Identification Number | VIN | Number assigned to the vehicle by the manufacturer, primarily for licensing and identification purposes |
| Vehicle Interface Adapter | VIA | Extends the PDU capability and provides a parallel interface to vehicle harnesses and ECMs |
| Vehicle Speed Sensor | VSS | Sensor which provides vehicle speed information |
| Viscosity Index | VI | |
| Voltage Regulator | VR | Device which regulates the variable output voltage of a generator |
| W | ||
| Watt | W | SI unit of power (1 hp = 745.7 watts) |
| Wide Open Throttle | WOT | Full throttle position |