ABS: Anti—lock Brake System.
A/C: Air Conditioning. A vehicle accessory system that modifies the passenger compartment air by cooling and dehydrating the air.
ACC: Air Conditioning Clutch. Indicates status of the A/C clutch.
ACCS: Air Conditioning Cycling Switch. Indicates status of the A/C cycling switch.
ACD: Air Conditioning Demand. A signal input to the PCM from the Air Conditioning control panel.
ACP: Air Conditioning Head Pressure or A/C cycling switch input state.
ACPSW: Air Conditioning Pressure Switch.
ACP V: Air Conditioning Head Pressure Volts. A voltage input to the PCM from the ACP switch or sensor.
ACR: Air Conditioning Relay. Commanded output controlled by the PCM and acts as an A/C cutout control during heavy acceleration.
A/D: Analog—to—Digital. Analog—to—Digital signal conversion.
ADC: See ATDC.
AFCM: Alternative Fuel Control Module.
AIR: Secondary Air Injection.
AIRB: Secondary Air Injection Bypass.
Air Dirverter: Air Diverter Valve. Part of the EAIR system. Diverts fresh air to the
exhaust system when the electric air pump is commanded on.
AIR EVAL: Air System Evaluated. Displays a YES or NO status indicating whether the Air System has been evaluated for OBD (On—Board Diagnostic) II purposes.
Air/Fuel Ratio: Air to fuel mixture ratio. An air/fuel mixture that is 14.7:1 is also called stoichiometry.
AIRM: Secondary AIR pump monitor.
Ambient Air Temperature: Temperature of the air surrounding an object.
Analog (Electrical/Electronic): An electrical signal that can obtain any value within the voltage limits of the signal.
ARB: Air Resource Board.
ARPMIDES: Ancillary RPM Desired. RPM required to maintain the vehicle speed commanded by Speed Control Command Switch (SCCS) inputs.
ASCII: American Standard Code for Information Interchange.
ATDC: After Top Dead Center. The location of the piston after it has reached the top of its stroke. Measured in degrees of crankshaft rotation.
AVOM: Analog Volt—Ohm Multimeter. Readings are indicated by a sweep hand on a printed scale, rather than a digital display.
AWD: All—Wheel Drive.
BARO: Barometric Pressure.
Base Idle: Idle rpm determined by the throttle lever hardset on the throttle body with the IAC solenoid disconnected.
Base Timing: Spark advance in degrees before top dead center of the base engine without any control from the PCM or ICM.
Battery Positive Voltage (B+): The positive (+) voltage from the battery or any circuit connected directly to the battery. Compare "Vehicle Power (VPWR)."
BATTEMP: Battery Temperature.
BJB: Battery Junction Box.
BOB: Breakout Box. A test device which connects in series to the PCM and PCM harness.
BPA: Brake Pedal Applied switch. Typically located on the braking system master cylinder. Can be hydraulic or electric.
BPP: Brake Pedal Position. Indicates the position of the brake pedal, based on input from the Brake Pedal Position (BPP) switch.
BRAKE _LMP or BRKL: Brake Warning Lamp Status. Activates the Brake Warning Lamp by applying voltage to the control line.
BTDC: Before Top Dead Center. The location of the piston before it has reached the top of its stroke. Measured in degrees of crankshaft rotation.
Bus + or Bus — : Multiplex circuits that carry SCP data from module to module and to the DLC.
CAC: Charge Air Cooler. Formerly known as Intercooler. A device which lowers the temperature of pressurized intake air.
CAFE: Corporate Average Fuel Economy. A set of federal requirements and regulations which govern fuel economy standards.
CANVNT: Canister Vent Solenoid.
Catalyst: Catalytic converter. An in—line exhaust system device used to reduce the level of engine exhaust emissions.
CAT EVAL: Catalyst System Evaluated. This item indicates YES when the Catalyst Efficiency Monitor has successfully completed.
CCM: Comprehensive Component Monitor.
CCRM: Constant Control Relay Module. A relay module that provides ON—OFF control of various EEC components.
CD A through J: Coil Driver 1 through 10.
Centralized Testing Facility: State government operation. Provides Inspection/Maintenance (IM) and safety inspections.
CGND or CSE GND: Case Ground. Provides a ground source for the PCM or ECU case.
CHT: Cylinder Head Temperature. Units are displayed in either degrees Fahrenheit or Centigrade.
CHTIL: Cylinder Head Temperature Indicator Lamp.
CHTV: Cylinder Head Temperature Voltage. The actual voltage drop across the CHT sensor thermistor.
CID: Cylinder Identification. PCM input signal from
Camshaft Position Sensor.
CKP: Crankshaft Position. Senses the position of the crankshaft.
CKP+, CKP—: CKP+ is the Crankshaft Position (CKP) sensor signal wire. CKP— is the signal return.
CL: Closed Loop. An operating condition or mode which enables operation based on sensor feedback.
CMP: Camshaft Position. Indicates camshaft position.
CMPFM: Camshaft Position Failure Mode. Indicates when the PCM identifies a CID/CMP fault.
CMS: Catalyst Monitor Sensor. Downstream HO2S.
CMVSS: Canadian Motor Vehicle Safety Standards.
CNG: Compressed Natural Gas.
CO: Carbon Monoxide. A colorless, odorless and toxic gas that is a component of auto exhaust emissions.
CO 2 : Carbon Dioxide. A colorless, odorless gas that is a normal by—product of the combustion of fuel.
Coil: A device consisting of windings around an iron core. In a spark ignition system, designed to increase voltage.
Cold Soak: Time given to a vehicle to sit at a low temperature (typically below 68° F / 20° C) until the temperature of external and internal components stabilize.
CONT: Continuous Memory. The portion of KAM (keep alive memory) used to store DTCs generated during Continuous Memory Self—Test.
Continuous Memory Self—Test: A continuous test of the EEC system conducted by the PCM whenever the vehicle is operating.
CPP: Clutch Pedal Position. Indicates clutch pedal position.
CPP Switch: Clutch Pedal Position Switch. Located on the clutch pedal and detects when the clutch pedal is depressed.
CQIS: Common Quality Indicator System.
CSE GND: Case Ground.
CT: Closed Throttle Mode. A mode when the PCM varies the pulse width of the fuel injectors to obtain the air/fuel mixture appropriate for closed throttle operation.
CTO: Clean Tach Output. Signal used to drive the instrument panel tachometer.
Data Communications Link: A communication path between various in—vehicle electronic modules. Accessed by scan tools through the Data Link Connector (DLC).
DC: 1. Direct Current. Electric current flowing in one direction. 2. Duty Cycle. The voltage measurement of ON time versus the full cycle period, expressed in percent.
DCL: Data Communication Link.
DI: Distributor Ignition. A system in which the ignition coil secondary circuit is sequenced by a distributor.
Digital: Controls process infromation by switching the current or voltage ON and OFF.
DLC: Data Link Connector. J1962 connector providing access to vehicle diagnostic information.
DOHC: Dual Overhead Cam. An engine configuration that uses two camshafts positioned above the valves.
DOL: Data Output Line. A circuit that sends certain information from the PCM to the instrument cluster.
DPFEGR: Differential Pressure Feedback Exhaust Gas Recirculation. System that uses a pressure transducer to control the operation of the
EGR Vacuum Regulator Valve.
DRI: Deposit Resistant Injector. A fuel injector designed to prevent build—up of carbon and other unwanted deposits.
DRL: Daytime Running Lamps. A system that keeps the vehicle running lamps on at all times while the vehicle is operating.
DTM: Diagnostic Test Mode. A level of capability in an On—Board Diagnostic (OBD) system.
DTC: Diagnostic Trouble Code. An alpha/numeric identifier for a fault condition identified by the On—Board Diagnostic System.
DVOM: Digital Volt—Ohm Meter.
E—85: Fuel containing 85% ethanol alcohol.
EAIR: Electric Secondary Air Injection. A pump—driven system for providing secondary air using an electric air pump.
EAIRM: Electric Secondary Air Pump circuit Monitor.
ECT: Engine Coolant Temperature. Displayed in either Fahrenheit or Centigrade.
ECTV: Engine Coolant Temperature Voltage. The actual voltage drop across the ECT sensor thermistor.
ECU: Electronic Control Unit. A module that handles the control strategy and monitors system inputs or outputs.
EEC: Electronic Engine Control system.
EEC—V: Fifth generation EEC system.
EFT: Engine Fuel Temperature.
EFTA: Bank 1 input. EFTA is displayed in either Fahrenheit or Centigrade.
EFTAV: Voltage drop across the EFTA (Bank 1) sensor thermistor.
EFTB: Bank 2 input. EFTB is displayed in either Fahrenheit or Centigrade.
EFTBV: Voltage drop across the EFTB (Bank 2) sensor thermistor.
EGR: Exhaust Gas Recirculation. A process in which a small amount of exhaust gas is routed into the combustion chamber.
EGR EVAL: Exhaust Gas Recirculation System Evaluated. EGR EVAL will display YES when the monitor is complete.
EGRMDSD: Electric Exhaust Gas Recirculation Motor Desired position. The PID name used to operate the EEGR valve with scan tool's output state control.
EGRS: EGR Shutoff. A normally closed
solenoidthat applies vacuum to the EGR valvewhen energized by the PCM.
EGRT: Exhaust Gas Recirculation Valve Temperature Sensor. A temperature sensor that is threaded into the bottom of the
intake plenum.
EGR Vacuum Regulator: Controls vacuum to the EGR valveby a duty cycle signal from the PCM.
EGRVR: Exhaust Gas Recirculation Vacuum Regulator. Solenoidwhich varies the vacuum to the EGR valveby varying the duty cycle to the regulator.
EGRVRA: Exhaust Gas Recirculation Vacuum Regulator Actual (volt). The actual state of the commanded output.
EGRVRF: Exhaust Gas Recirculation Vacuum Regulator Fault. Represents whether a fault exists in the EGRV circuit.
EI: Integrated Electronic Ignition. An Electronic Ignition system that has the Ignition Control Module(ICM) integrated into the PCM.
EI—HDR: Electronic Ignition, High Data Rate. Formerly known as Electronic Distributorless Ignition System.
EI—LDR: Electronic Ignition, Low Data Rate. Formerly known as Distributorless Ignition System.
EMI: Electromagnetic Interference. Usually caused by ignition voltage spikes, solenoids, relay operation or noisy generator contacts.
EOL: End Of Line. A system designed specifically for use at assembly plants to make sure all new vehicles perform to design specifications.
EPA: Environmental Protection Agency (U.S. Government).
EPROM: Erasable Programmable Read—Only Memory. An electronic component in the PCM that requires the electronic storage of information.
ESOF: Electronic Shift—on—the—Fly.
EVAP: Evaporative Emissions. A system to prevent fuel vapor from escaping into the atmosphere.
EVAPCP: Evaporative Canister Purge Solenoid. Controls a solenoidwhich allows venting of the evaporative purge canister.
EVAPCPF: Evaporative Canister Purge SolenoidFault. Identifies whether an electrical fault exists for the current commanded state.
EVAPCV: Evaporative Canister Vent Solenoid. Controls a solenoidwhich seals the EVAP system canister from atmospheric pressure during the EVAP OBD II Monitor test.
Evaporative Emissions Canister: An evaporative emission canister, containing activated charcoal which absorbs and holds fuel vapors.
EVAPPDC: Evaporative Canister Purge Duty Cycle. The duty cycle commanded to the Evap Canister Purge Solenoidby the PCM.
EVO: Electronic Variable Orifice.
EWP: Electric Water Pump.
Exciter Ring: A toothed or notched iron or steel disk, which is the moveable part of a wheel speed sensor.
FAN: Fan Speed. Used in conjunction with vehicles having multiple fan speed control. Displays OFF, LOW, or HIGH status.
FC: Fan Control.
FCS: Fuel Control Solenoid.
FCIL: Fuel CapOff Indicator Lamp. Indicates that the fuel filler cap was not properly installed.
FEAD: Front End Accessory Drive.
FEPS: Flash EEPROM Programming Signal. 18 volt DC signal sent by the scan tool to initiate PCM reprogramming.
FF: 1. Flexible Fuel. A system capable of using a variety of fuels for vehicle operation. 2. A PID that displays the % alcohol content in fuel.
FF_LRN: Flex FuelLearned. Displays when the PCM's Flex Fuelstrategy has completed calculating the inferred alcohol content of fuel.
FFFM: Flexible Fuel Failure Mode. Indicates whether the current Flex FuelSensor reading (FF) is reliable or not. Displays a YES or NO.
FF_TEMP: Flexible Fuel Sensor — Temperature. Alcohol concentration derived from the signal pulse width.
FFV: Flexible Fuel Vehicle.
FIFO: First In First Out.
FILO: First In Last Out.
FIM: Fuel Indicator Module.
FLI: Fuel Level Input. Used by the Evap monitor to calculate fuel tank vapor volume. Displayed as a percentage.
FLI V: Fuel Level Input Voltage.
FMEM: Failure Mode Effects Management. Operating strategy that maintains limited vehicle function in the event of a PCM or EEC component failure.
FP: 1. Fuel Pump. Indicates whether the pump has been commanded ON or OFF by the PCM. 2. Fuel Pump (Modulated). Fuel pump duty cycle percentage.
FPDM: Fuel Pump Driver Module. A module that controls the electric fuel pump.
FPF: Fuel Pump Fault. Identifies whether a fault exists in the FP circuit.
FPM: Fuel Pump Monitor. Monitors the Fuel Pump / circuits for faults.
Freeze Frame: A block of memory containing the vehicle operating conditions at a specific time.
FRP: Fuel Rail Pressure. Based on FRP V.
FRP V: Fuel Rail Pressure Voltage. A voltage input to the PCM from the Fuel Rail Pressure Sensor.
FSC: Fail—Safe Cooling.
FSV: Fuel Shut—Off Valve. A component of Natural Gas Vehicles. This valve either allows or prevents Natural Gas flow to the fuel rail.
FSVF: Fuel Shut—Off Valve Fault. Indicates if there is a fault in the FSV circuit. Displayed as YES or NO.
FSVM: Fuel Shut—Off Valve Monitor. Monitors operation of the Fuel Shut—Off Valve / circuit.
FTP: Fuel Tank Pressure. Displayed as inches of water, kPa, or volts.
FTP V: Fuel Tank Pressure Voltage. From the FTP transducer.
FUEL PR: Fuel Pressure. Measurement of the force of the fuel delivered via the fuel pump.
FUELPW: Fuel Pulse Width. Displays the commanded pulse width at time of last data update.
FUELPW1:
Fuel InjectorPulse Width #1. Corresponds to injectors normally affected by O2S1 (HEGO1).
FUELPW2: Fuel InjectorPulse Width #2. Corresponds to injectors normally affected by O2S2 (HEGO2).
FUELSYS: Fuel System Status (OPEN/CLOSED Loop). Formerly known as LOOP.
Fuel Tank Vapor Valve: A valve mounted in the top of the fuel tank that vents excess vapor and pressure from the fuel tank into the Evaporative Emission Control System.
FWD: Front Wheel Drive.
GEM: Generic Electronic Module.
GEN: Generator.
GENF: Generator output fault.
GENFDC: Generator field control output.
GFS: Generator field signal monitor.
GND: Ground.
GPM: Grams Per Mile. Also known as Gallons Per Minute.
GPS: Global Positioning Satellite.
Green State Vehicle: Formally known as California Emissions. A vehicle that is equipped with California on—board diagnostics.
GSS: Gear Select Solenoid.
GVW: Gross Vehicle Weight.
Hall Effect: A process where current is passed through a small slice of semi—conductor material and a magnetic field to produce a small voltage in the semi—conductor.
Hard Fault: A fault currently present in the system.
HC: 1. Hydrocarbon. A by—product of combustion and a component of auto exhaust emissions. 2. High Compression.
HCF: Hydraulic Cooling Fan.
HCFD: Hydraulic Cooling FanDrive.
HFC: Hydraulic Cooling Fan.
HFCF: High Fan Control Fault. Identifies if there is a fault in the HFC circuit.
HFP: High Fuel Pump.
HLOS: Hardware Limited Operating Strategy. A mode of operation where the PCM replaces output commands with fixed values in response to internal PCM malfunctions.
HO: High Output.
HO2S: Heated Oxygen Sensor. Formerly known as Heated Exhaust Gas Oxygen (HEGO) Sensor. Provides information on rich or lean exhaust conditions to the PCM.
Hot Soak: Period of time after an engine operates where localized combustion heat dissipates throughout the engine.
HTR, HTR11, HTR12, HTR21, HTR22, HTRX1, HTRX2: HO2S Heater. Heater element for the HO2S sensor.
Hydrogen: Chemical symbol H. Highly flammable gas.
Hz: Hertz. Cycles per second.
IAC: Idle Air Control. Electrical control of throttle bypass air.
IAT: Intake Air Temperature.
IATV: Intake Air Temperature Voltage. Actual voltage drop across the IAT sensor.
IAT2: Intake Air Temperature 2. Displayed in either Fahrenheit or Centigrade. Used on supercharged vehicles.
IAT2V: Intake Air Temperature 2 Voltage. Actual voltage drop across the IATV2 sensor.
IC: Integrated Circuit. A small semi—conductor device capable of doing many separate circuit functions.
ICM:
Ignition Control Module. The module that controls the ignition system.
IFDM: Integrated Fuel Delivery Module.
IFS: Inertia Fuel Shutoff.
IGN GND: Ignition Ground.
Ignition: System used to provide high voltage spark for internal combustion engines.
IGN_KEY (IGKY): Ignition Key status.
IGN_SW (IGSW): Ignition Switch Position.
IMRC: Intake Manifold Runner Control. Controls airflow through the high—speed runners in the intake manifold.
IMRCM: Intake Manifold Runner Control Monitor. Monitors the IMRC / circuits for faults.
IMTV: Intake Manifold Tuning Valve. Controls airflow through runners in a split intake manifold.
INJ1, INJ2, INJ3, INJ4, INJ5, INJ6, INJ7, INJ8, INJ9, INJ10: Injector number or its signal output from the PCM.
Injector: A device for delivering metered pressurized fuel to the intake system or the cylinders.
Intake Air: Air drawn through a filter and distributed to each cylinder for use in combustion.
Intercooler: See CAC.
IPATS: Integrated Passive Anti—Theft System.
ISO: International Standards Organization.
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. Dedicated, unswitched power circuit that maintains KAM.
Key On Engine Off Self—Test: A test of the EEC system conducted by the PCM with power applied and the engine at rest.
Key On Engine Running Self—Test: A test of the EEC system conducted by the PCM with the engine running and the vehicle at rest.
KEYPWR: Key Power. Battery voltage supplied when the ignition key is in the ON position.
Knock: The sharp metallic sound produced when two combustion pressure fronts collide in the combustion chamber of an engine.
KOEC: Key On Engine Continuous.
KOEO: Key On Engine Off.
KOER: Key On Engine Running.
KPA: Kilopascal. Unit of pressure. 3.386 kPa = 1 inch of mercury (Hg.).
KPH: Kilometers Per Hour.
KS: Knock Sensor. Detects engine knock.
L: Liters. The unit of volume in the metric measuring system. One liter equals 1.06 quarts.
LEV: Low Emissions Vehicle.
LFC: Low Fan Control.
LFP: Low Fuel Pump. Reduced operating speed for multi—speed fuel pumps.
LIFO: Last In First Out.
LILO: Last In Last Out.
LONGFT1, LONGFT2: Long—Term Fuel Trim. Fuel flow adjustment determined by the PCM.
LOOP: Indicates OPEN or CLOSED loop status.
LPG: Liquefied Petroleum Gas.
LPLR: Low Pressure Low Resistance
fuel injector.
M—85: Fuel containing 85% methanol alcohol.
MAF: Mass Air Flow. Used to measure the mass (weight) of the air entering the engine.
MAF RTN: Mass Air Flow Return. A return circuit for the MAF sensor.
MAP: Manifold Absolute Pressure. The internal pressure of the intake manifold.
MFC: Medium Fan Control.
MFI: Multiport Fuel Injection. A fuel—delivery system in which each cylinder is individually fueled.
MFP: Modulated Fuel Pump.
Microprocessor: A digital processor on a chip which performs arithmetic and control logic.
MIL: Malfunction Indicator Lamp. An indicator lamp alerting the driver of an emission related malfunction. May also read "CHECK ENGINE" or "SERVICE ENGINE SOON."
MISF: Misfire. Any event in the cylinder that causes a sudden change in acceleration of the crankshaft.
MON: Motor Octane Number.
Monolithic Substrate: The ceramic honeycomb structure used in the catalytic converter.
MSOF: Manual Shift—on—the—Fly.
MY: Model Year.
NA: Naturally Aspirated. Engine that is not supercharged or turbocharged.
NAAO: North American Automotive Operations.
NC: Normally Closed.
NG: Natural Gas. A system capable of using natural gas for vehicle operation.
NGS: New Generation STAR (Self—Test Automatic Readout) tester.
NGVM: Natural Gas Vehicle Module.
NO: Normally Open.
NO X : Oxides of Nitrogen. Formed at high combustion temperatures.
NVH: Noise, Vibration, Harshness. A classification of vehicle concerns.
OASIS: On—line Automotive Service Information System.
OBD, OBD—II: On—Board Diagnostics, On—Board Diagnostics Second Generation. A system that monitors PCM input and output control signals.
On—Demand Test: Technician initiated "KOEO" and "KOER" tests performed by the PCM.
OC: Oxidation Catalytic converter. A catalytic convertersystem that reduces levels of HC and CO.
OCT ADJ: Octane Adjust. Compensating strategy that adjusts for changes in fuel octane.
OEM: Original Equipment Manufacturer.
OHC: OverHead Cam. An engine configuration that uses a single camshaftpositioned above the valves.
OWL: Overheat Warning Lamp or its signal output from the PCM. Turns the TEMP warning lamp ON when engine oil temperature exceeds safe limits.
Open Circuit: A circuit which does not provide a complete path for flow of current.
OL: Open Loop. An operating condition based on instructions not modified by PCM feedback.
O 2 S 11/12/21/22: Oxygen Sensor and its relative position in the
exhaust system. Detects oxygen content in exhaust gasses.
OSC: Output State Control.
OSS: Output ShaftSpeed.
Ozone: A blue gaseous form of oxygen (O 3 ) formed naturally by electric discharge or exposure to ultraviolet radiation.
Particulate: Small solid matter found in exhaust gases, especially prevalent in diesel engines.
PATS: Passive Anti—Theft System.
PATSIL: Passive Anti—Theft System Indicator Light.
PATSIN: Passive Anti—Theft System Receive Signal.
PATSOUT: Passive Anti—Theft System Transmit Signal.
PATSTRT: Passive Anti—Theft System Starter RelayControl
PCM: Powertrain Control Module. Formerly known as the EEC (Electronic Engine Control) Processor.
PCV: Positive Crankcase Ventilation. A system which allows the controlled flow of crankcase vapors into the combustion chamber.
PF: Purge Flow. Amount of fuel vapor burned in the engine.
Photochemical: Term describing the action of light on air pollutants which results in creating smog.
PID: Parameter Identifier. Identifies an address in PCM memory which contains operating information.
Powertrain: Engine and transmission/transaxle components.
Pressure — Absolute: A pressure referenced to a perfect vacuum.
Pressure — Atmospheric: The pressure of the surrounding air at any given temperature and altitude. Sometimes called Barometric Pressure.
Pressure — Barometric: Pertaining to atmospheric pressure or the results obtained by a barometer.
Pressure — Differential: The pressure difference between two regions, such as between the intake manifold and atmospheric pressure.
Pressure — Gage: The amount by which absolute pressure exceeds the ambient atmospheric pressure.
PIP: Profile Ignition Pickup. Provides crankshaft positioninformation for ignition synchronization.
Potentiometer: An adjustable resistance component commonly used as a sensor (Example: TP Sensor).
PPM: Parts Per Million. A measure used in emission analysis.
PROM: Programmable Read—Only Memory. Similar to ROM except without program instructions.
Protocol: A set of rules for the exchange of information on a network.
PSOM: Programmable Speedometer/Odometer Module. A module that processes vehicle speed information.
PSP: Power Steering Pressure. Indicates the pressure in the power steering system.
PSP V: Power Steering PressureInput Voltage.
PTEC: PowerTrain Electronic Controller.
PTO: Power Take—Off.
PW: Pulse Width. The length of time an actuator, such as a fuel injector, remains energized.
PWM: Pulse Width Modulation. Controls the intensity of an output by varying the signal duty cycle.
PWR GND: Power Ground. The main ground circuit in the EEC system.
Quick Test: A series of diagnostic tests of the EEC system consisting of KOEO, KOER and Continuous Memory Self—Tests. Results are displayed as a series of DTCs.
RABS: Rear Antilock Brake System.
RAM: Random Access Memory. Memory into which information can be written as well as read.
REDOX: Reduction Oxidation
Catalytic converter. A catalytic convertersystem designed to operate at high temperatures.
Regulator: Controls the alternator/generator field current to maintain proper battery charge. Contained within the PCM in smart charging applications.
Relay: An electromechanical device in which connections in one circuit are opened or closed by changes in another circuit.
REM: Rear Electronic Module.
Repetitive Spark: Multiple firings of individual spark plugs at engine speeds below 1000 RPM to improve idle quality and improve emissions.
RF: Radio Frequency.
RFI: Radio Frequency Interference.
RFS: Returnless Fuel System.
RM: Relay Module. A module containing two or more relays.
ROM: Read—Only Memory. Computer memory that can be accessed and utilized, but not altered.
RON: Research Octane Number.
Routine: A group of related tasks, such as a series of diagnostic tests.
RPM: Revolutions Per Minute.
RS: Reverse Switch.
RTN: Return. A dedicated sensor ground circuit.
RWD: Rear Wheel Drive.
SAE: Society of Automotive Engineers.
SBS: Supercharger Bypass Solenoidor its signal output from the PCM.
SC: Supercharged or Supercharger.
SCB: Supercharger Bypass Control. A system that allows manifold vacuum to be bled away from the supercharger wastegate actuator to allow for maximum boost.
SCBF: Supercharger Bypass Control Fault. Identifies whether a fault exists in the Supercharger Bypass circuit.
SCICP: Supercharger Intercooler Pump Control.
SCICPF: Supercharger Intercooler Pump Control Fault.
SCIPC: The PID to monitor the operation of the Supercharger and Charge Air Cooler pump.
SCP: Standard Corporate Protocol.
Self—Test: See Quick Test.
Sensor: A device that detects the value or change in a physical quantity, such as temperature, pressure or flow rate, and converts the data into an electrical signal.
SFI: Sequential Multiport Fuel Injection. A multiport fuel delivery system where each injector is individually energized and timed relative to its cylinder intake event.
Shield: A conducting sleeve that surrounds wires to be electronically isolated from electromagnetic interference (EMI).
Short Circuit: An undesirable condition in a circuit where it is terminated at a point other than that intended.
SHRT FT: Short—Term Fuel Trim. Fuel flow adjustment in response to the HO2S sensor(s) input during closed—loop operation.
SIG RTN: Signal Return. A dedicated sensor ground circuit that is common to two or more sensors.
SIL: Shift Indicator Lamp.
Smart Driver: A PCM or ECU output driver that can detect faults (open or shorts) on its output circuit.
SME: Society of Manufacturing Engineers.
SOF: Shift—On—the—Fly.
SOHC: Single Overhead Cam.
Solenoid: A device consisting of an electrical coil which produces a magnetic field in a
plungerand pulled to a central position.
ST: Scan Tool. A device that interfaces with and communicates information on a data link.
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.
Switch: A device for making, breaking, or changing the connections in an electrical circuit.
TA: Traction Assist.
TACH: Tachometer.
TB: Throttle Body. A device that controls airflow through the engine via a butterfly valve, and has an air bypass channel around the throttle plate.
TC: 1. Traction Control. Combines anti—lock braking and axle torque reduction to control wheel slippage. 2. Turbocharger.
TDC: Top Dead Center.
Tear Tag: The two—piece adhesive label attached to the PCM to identify its calibration.
Thermistor: A temperature dependent resistor, like that used in CHT and ECT sensors.
Timing: Relationship between spark plug firing and piston position expressed in crankshaft degrees before (BTDC) or after (ATDC) top dead center of the compression stroke.
TMAP: Thermal Manifold Absolute Pressure Sensor. A MAP Sensorthat includes a thermistor to measure intake air temperature.
TP: Throttle Position (sensor). A three—wire potentiometer that provides throttle angle and rate information for the PCM.
TP V: Throttle Position SensorVoltage.
Transducer: A device that receives energy from one medium and transfers it to another. For example, thermal energy is converted to an electrical signal through a temperature probe.
TSB: Technical Service Bulletin. Notifies service personnel of any known vehicle concerns, procedures, or general service information.
Underspeed Mode: A control mode that prevents the engine from stalling in the event it stumbles while running. Also used during engine crank.
Vacuum: Manifold pressure that is reduced below the ambient atmospheric pressure.
Variable Reluctance: A process of passing a varying magnetic field through wire windings and inducing a voltage.
VCT: Variable CamshaftTiming.
VECI: Vehicle Emission Control Information label.
VIN: Vehicle Identification Number. A unique identification number given to every vehicle produced. Includes information about the year, model, engine, and plant origin of the vehicle.
VMV: Vapor Management Valve. Controls the flow of fuel vapors out of the carbon canister.
VOM: Volt—Ohm Meter. Readings are indicated by sweep hand on a printed scale rather than a digital (DVOM) display.
VPWR: Vehicle Power. A switched circuit that provides power to the EEC system. Compare "Battery Voltage (B+)."
VREF: Reference Voltage. A dedicated circuit that provides approximately a 5.0 volt signal used as a reference by certain sensors.
WAC: Wide Open Throttle A/C Cut—Off. Turns A/C system off during wide open throttle or certain other operating conditions.
Wastegate Control: A device that opens the wastegate in case of overboost from a turbocharger.
WOT: Wide Open Throttle. A condition of maximum airflow through the throttle body.
Zip Tube: Another name for "fresh air duct" or "air inlet duct".
T R A N S M I S S I O N S :
Note: The transmission naming convention is as follows:
The first character, a number, is the number of forward gears.
The second character, either the letter "F" or "R," represents front (transaxle) or rear (transmission) wheel drive.
The next set of characters, a grouping of numbers, represents the design torque capacity of the transmission/transaxle (for example, "27" represents 270ft./lbs. in the 4F27E transaxle).
The last character, if used, is one of the following:
"E" for electronic shift
"N" for non—synchronous shift
"S" for synchronous shift
"W" for wide ratio
4F27E: Also known as the FN Focus automatic transmission.
4F44E: Formerly known as the CD4E.
4F46S: Formerly known as the AX4S and regular—duty AXOD—E.
4F50N: Formerly known as the AX4N and heavy—duty AXOD—E.
4R44E: Formerly known as A4LD for 3.0L applications.
4R55E: Formerly known as A4LD for 4.0L applications.
4R70W: Formerly known as AOD—E.
4R100: Formerly known as E4OD.
5R44E: Formerly known as A5LD for 3.0L applications.
5R55E: Formerly known as A5LD for 4.0L applications.
5R55N: Lincoln LSautomatic transmission.
5R55W: Wide—ratio truck transmission.
4x4L: 4x4 Low.
A/T: Automatic Transmission.
CCS: Coast Clutch Solenoid.
CCSF: Coast Clutch SolenoidFault. Displays a YES if fault exists.
EPC: Electronic Pressure Control.
EPCV: Electronic Pressure Control Volts.
ESS: Electronic Shift Scheduling.
HCDSS: High Clutch Drum Speed Sensor. PCM input from the 4R44E and 4R55E.
M5OD: Manual 5—Speed transmission with overdrive (RWD).
M/T: Manual Transmission/Transaxle.
NPS: Neutral Pressure Switch or its signal input to the PCM.
OCS: Overdrive Cancel Switch.
OSS: Output ShaftSpeed. Indicates rotational speed of the transmission output shaft.
PNP: Park/Neutral Position switch. Also known as Neutral Drive Switch (NDS), Neutral Gear Switch (NGS), and Transmission Switch Neutral (TSN).
REVERSE or REV: Transmission Reverse Switch Input.
SIL: Shift Indicator Lamp. A lamp that indicates the preferred shift points on select manual transmission/transaxle vehicles.
SS1/SS2/SS3: Shift solenoids. Devices that control the shifting in an automatic transmission.
TCC: Torque ConverterClutch. When energized, causes a mechanical engagement and disengagement of the
Torque ConverterClutch.
TCIL: Transmission Control Indicator Lamp. Indicates that the TCS has been activated.
TCS: Transmission Control Switch. Modifies the operation of electronically controlled transmissions.
Torque converter: A device which by its design multiplies the torque in a fluid coupling between an engine and transmission/transaxle.
TFT: Transmission FluidTemperature. Indicates temperature of transmission fluid.
Transaxle: A device consisting of a transmission and axle drive gears assembled in the same case. Front—wheel drive applications.
Transmission: A device which selectively increases or decreases the ratio of relative rotation between its input and output shafts. Rear—wheel drive applications.
TR: Transmission Range. The range in which the transmission is operating.
TR Sensor: Formerly known as Manual Lever Position Sensor (MLPS). Provides information to the PCM on the transmission range selector position.
TR V: Transmission Range Voltage.
TSS: Turbine Shaft Speed. Indicates rotational speed of the transmission turbine shaft.
VSS: Vehicle Speed Sensor. A magnetic pickup device that generates an AC signalthat is proportional to vehicle speed.
