Abbreviations and Glossary of Terms

Abbreviations And Glossary Of Terms
Abbreviations used are listed below in alphabetical order with an explanation of the abbreviation. All the terms listed below subscribe fully to the S.A.E. requirements for 1996.

Amperage Or Current
The rate of flow of electrons is similar to gallons of water per minute flowing in a water pipe.

Analog Signal
An electrical signal which varies in voltage within a given parameter.

B+
Battery Positive terminal (12 volts).

BARO
Sensor which measures atmospheric pressure.

Capacitor
An electrical device used to store a temporary charge.

Catalytic Converter
Containing platinum and palladium to speed up conversion of HC and CO.

CID - Cubic Inch Displacement
Used to describe engine size.

CO - Carbon Monoxide
One of the pollutants found in engine exhaust.

Control Module System
Utilizes one of three control modules (ECM, PCM and VCM) to control air/fuel and emission systems.

Control Solenoid
An electrical switching device used to operate another system.

Crankcase Vent Valve
Prevents fumes in crankcase from passing into atmosphere.

Diagnostic Terminal
Grounding terminal "B" of Data Link Connector (DLC) will flash or display a DTC. When grounded with the engine operating the vehicle will enter the "Field Service Mode."

DTC
A specific set of numbers obtained from flashing the MIL (Service Engine Soon), or displaying on a scan tool. These DTC(s) are used to determine the system malfunctions.

Diode
An electrical device that restricts current flow in one direction.

DLC - Data Link Connector
Used at the assembly plant to evaluate the vehicle's control module system and for service for DTCs. Also can be used by scan tools to obtain control module serial data, for service diagnosis.

DVM (10 Meg.)
Digital voltmeter with 10 million ohms resistance - used for measurement in electronic systems.

EMI Or Noise
An unwanted signal interfering with another needed signal; like an electrical razor upsets a television picture, or driving under high voltage power lines upsets the AM radio in a vehicle.

Energize/De-Energize
When current is passed through a coil (energized) such as a solenoid, a plunger is pulled or pushed. When the voltage to the solenoid is turned "OFF," (de-energized), a spring raises or lowers the plunger.

Engine Coolant Temperature (ECT) Sensor
Device that senses the engine coolant temperature, and passes that information to the control module system.

Exhaust Gas Recirculation (EGR)
Method of reducing NOx emission levels.

Federal
Vehicle/engine available in all states except California.

Ground
A wire shorted to ground. A common return path for an electrical circuit. A reference point from which voltage measurements may be made.

HC - Hydrocarbons
One of the pollutants found in engine exhaust. Hydrogen and carbon in gasoline.

High Impedance DVM
Has high opposition to the flow of electrical current. Used for reading circuits with low current flow found in electronic systems.

IGN - Ignition
Refers to switched ignition voltage.

Inputs
Information from sources (such as, engine coolant temperature sensors, exhaust oxygen sensor, etc.) which tell the control module how the systems are performing.

Instrument Panel (I/P)
Contains instrument gages and indicator lights to indicate performance of the vehicle.

Intake Air Temperature (IAT)
The control module converts the resistance of the Intake Air Temperature (IAT) sensor into degrees. IAT is used by the control module to adjust fuel delivery and spark based on oncoming air density.

Intermittent
Occurs now and then; not continuously. In electrical circuits, refers to occasional open, short, or ground.

Kilometer Per Hour (km/H)
A metric unit measuring distance (1000 meters) in one hour.

Liter (L)
A metric unit of capacity.

Malfunction
A fault that causes the system to operate incorrectly. Typical malfunctions are; wiring harness opens or shorts, failed sensors, or circuit components.

Malfunction Indicator Lamp (MIL)
Lights when a malfunction occurs in the control module system.

Mercury (Hg)
A calibration material used as a standard for vacuum measurement.

Miles Per Hour (mph)
A unit measuring distance (5280 feet) in one hour.

Mode
A particular state of operation.

Newton Meters (Nm)
A metric unit of force.

Nitrogen NOx
One of the pollutants found in engine exhaust. Nitrogen that combines with oxygen to form oxides of nitrogen.

On-Board Diagnostic System Check
The control module will detect malfunctions in the system. If a malfunction occurs, the control module turns "ON" the MIL (Service Engine Soon). A DTC can be obtained from the control module through the MIL (Service Engine Soon) or scan tool. This DTC will indicate the area of the malfunction.

Output
Functions, typically solenoids, which are controlled by the control module.

Port
Exhaust Or Intake Port

Pressure Control Solenoid (Formerly Force Motor)
A solenoid used in the transmission to control shift quality.

Programmable Read Only Memory (PROM)
An electronic component which is specifically programmed to each vehicle model for control of fuel and emissions. The PROM is located in the control module.

Pulse Width Modulated (PWM)
A device operated by a digital signal controlled by the time duration the device is turned "ON" or "OFF."

Quad-Driver
A "chip" device that is capable of operating four separate outputs. Some have digital and some have pulse width modulated control.

Resistance
The ability of a circuit to limit current flow; like a restriction in a water pipe.

Revolutions Per Minute (RPM)
A measure of rotational speed.

Tachometer (TACH)
A device for indicating rotational speed of the crankshaft.

Torque Converter Clutch - TCC
Control module controlled solenoid in transmission which positively couples the transmission to the engine.

V6 - Six Cylinder Engine
Arranged in a "V".

Vacuum
Less than atmospheric pressure.

Vehicle Control Module (VCM)
Used on some vehicles to control and monitor not only fuel/air ratio and emissions, but also to control the electronic transmission operation.

Vehicle Speed Sensor (VSS)
Sensor which sends vehicle speed information to the control module.

VIN - Vehicle Identification Number
Appears on a plate attached to the windshield pillar.

Volt (V)
A measurement of electrical pressure.

Voltage
The pressure of force pushing the current in a circuit; like pressure in a water pipe.

VSS Buffer
An electrical signal that is either "ON" or "OFF" with no in between.

Wide Open Throttle (WOT)
Refers to the throttle plate or accelerator pedal when fully open.