Operation CHARM: Car repair manuals for everyone.

2V - L

ACRONYMS AND DEFINITIONS

NOTE: This Acronyms and Definitions listing contains technical terms applicable to Ford Motor Company products. It is not intended to be an all-inclusive dictionary of components and their functions. If a detailed description of a particular system or component is desired, refer to the applicable Vehicle System for the specific vehicle being serviced

2V - Two Valves per engine cylinder.

4V - Four Valves per engine cylinder.

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.

ACET - Air Conditioning Evaporator Temperature (may also be referred to as Evaporator Air Discharge Temperature).

ACP - Air Conditioning Head Pressure or A/C cycling switch input state.

ACPSW - Air Conditioning Pressure Switch.

ACPV - 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 Diverter - 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.

BRAKELMP 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.

CATEVAL - 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.

CO2 - 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 information 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 solenoid that applies vacuum to the EGR valve when 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 valve by a duty cycle signal from the PCM.

EGRVR - Exhaust Gas Recirculation Vacuum Regulator. Solenoid which varies the vacuum to the EGR valve by 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 solenoid which allows venting of the evaporative purge canister.

EVAPCPF - Evaporative Canister Purge Solenoid Fault. Identifies whether an electrical fault exists for the current commanded state.

EVAPCV - Evaporative Canister Vent Solenoid. Controls a solenoid which 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 Solenoid by 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.

FANSS - Fan Speed Sensor.

FC - Fan Control.

FCS - Fuel Control Solenoid.

FCIL - Fuel Cap Off Indicator Lamp. Indicates that the fuel filler cap was not properly installed.

FEAD - Front End Accessory Drive.

FEPS - Flash Electrically Erasable Programmable Read Only Memory (EEPROM) Programming Signal. 18 volt DC signal sent by the scan tool to initiate PCM reprogramming.

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.

FLIV - 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 FRPV.

FRPV - 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.

FTPV - 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 Injector Pulse Width #1. Corresponds to injectors normally affected by O2S1 (HEGO1).

FUELPW2 - Fuel Injector Pulse 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 Fan Drive.

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.

IGNKEY (IGKY) - Ignition key status.

IGNSW (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 Sell-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.