I often see that people have to ask when a technical acronym is posted here in the Tech Section therefore i present to you a list of the most used ones...

I hope it may be put to use

:cheers:

Daniel


A Through C Acronyms

A/T -- Automatic Transmission or Transaxle
A/C -- Air Conditioner
ACL -- Air Cleaner
AAT -- Ambient Air Temperature
AFGS -- Air Flow Grams per Second. The mass air flow reading., used on engines that have mass
flow meters.
AFR -- Air Fuel Ratio
ALDL -- Assembly Line Diagnostic Link. The serial data link from the PCM to the monitoring
computer. Also referred to as ALCL.
AP -- Accelerator Pedal
APP -- Accelerator Pedal Position
B+ -- Battery Positive Voltage
BARO -- Barometric Pressure. A measure of the atmospheric pressure
BLM -- Block Learn Multiplier. Now called Long Term Fuel Trim. The Long Term fuel correction
factor that the PCM is using.
BLM Cell -- Now called Fuel Trim Cell. Fuel Trim cells store Long Term correction factors that
correct for each engine’s unique operating conditions. A cell is active within a particular operating
region as determined by engine RPM and load. Most PCM's use 16 to 20 cells.
BPW -- Base Pulse Width. The length of time of the injector pulse, usually measured in Milliseconds
(1/1000 second).
2
BPP -- Brake Pedal Position
CAT -- Catalytic Converter
CCM -- Central Control Module. Used in Corvettes to communicate between the various on-board
computers. Also called body computer.
CCS -- Coast Clutch Solenoid
CCP -- Charcoal Canister Purge. Typically, there is a solenoid that controls when purge is active.
Used to control evaporative emissions.
CFI -- Continuos Fuel Injection. A fuel injection system whereby the injector flow is controlled by the
fuel pressure.
CL -- Closed Loop. An operating mode which allows modification engine control parameters based
on a feedback system.
CMP -- Camshaft Position
CTOX -- A system for lowering Diesel engine particulate emissions by collecting particulates and
continuously burning them through oxidation.
CKP -- Crankshaft Position
CPP -- Clutch Pedal Position

D Through F Acronyms

DC -- Duty Cycle. A value from 0 to 100%. The ratio of ON to OFF of a controlled device. A value of
0 means the device is OFF, a value of 25% means the device is 1/4 of full on.
DTC -- Diagnostic Trouble Code
DFI -- Direct Fuel Injection. A fuel injection system that supplies fuel directly into the combustion
chamber.
DI -- Distributor Ignition. A system in which the ignition coil secondary circuit is sequentially switched
by a distributor to the spark plugs
DLC -- Data Link Connector
DLI -- Distributor less Ignition, also called Electronic Ignition (EI). A system in which the ignition coil
secondary circuit is dedicated to specific spark plugs without the use of a distributor.
DRIVER -- An electronic switching device used to control an output state.
DTM -- Diagnostic Test Mode. Any of various PCM Test modes that allow the observation and control
of PCM signals.
DTC -- Diagnostic Trouble Code
EATX -- Electronic Automatic Transmission/Transaxle.
ECM -- Engine Control Module
ECL -- Engine Coolant Level
3
ECT -- Engine Coolant Temperature
EDF -- Electro Drive Fan Control
EECS -- Evaporative Emission Control System
EFI -- Electronic Fuel Injection
EGO, EGOS -- Exhaust Gas Oxygen Sensor (O2S)
EGR -- Exhaust Gas Recirculation. Reduces Nox emissions by adding exhaust gas to the incoming
air/fuel mixture.
EGRT -- EGR Temperature
EGRV -- EGR Vacuum Regulator Valve
EOP -- Engine Oil Pressure
EOT -- Engine Oil Temperature
EP -- Exhaust Pressure
EPROM -- An electronic memory device which is erasable and reprogrammable
EI -- Electronic Ignition. A distributorless ignition system in which the ignition coil secondary circuit is
dedicated to specific spark plugs without the use of a distributor.
EVAP -- A system used to prevent fuel vapor from escaping into the atmosphere. Typically includes a
charcoal canister to store fuel vapors.
EVP -- EGR Valve Position
F4WD -- Full-time Four Wheel Drive
FBC -- Feed Back Control or Feed Back Carburetor
FC -- Fan Control
FI -- Fuel Injection
FREEZE FRAME -- A block of data containing vehicle operating conditions for a specific instance.
FP -- Fuel Pump
FT -- Fuel Trim. A fuel correction term.
FWD -- Front Wheel Drive
4

G Through O Acronyms

GEN -- Generator
GCM -- Governor Control Module
GPM -- Grams Per Mile
GND -- Ground. An electrical conductor used as a common return for an electrical circuit
HEI -- High Energy Ignition
HO2S -- Heated Oxygen Sensor
IA -- Intake Air
IAC -- Idle Air Control
IACV -- Idle Air Control Valve
IAT -- Intake Air Temperature
IC -- Ignition Control
ICM -- Ignition Control Module
ICP -- Injection Control Pressure
IFS -- Inertia Fuel Shut-off
ISC -- Idle Speed Control
ISS -- Input Shaft Speed
IMRC -- Intake Manifold Runner Control
INT -- Integrator. Now called Short Term Fuel Trim. The Short Term fuel correction factor that the
PCM is using.
KS -- Knock Sensor
LTerm, Long Term -- Long Term Fuel Trim (previously called Block Learn)
MAF -- Mass Air Flow
MAP -- Manifold Absolute Pressure
MAT -- Manifold Temperature
MFI -- Multipoint Fuel Injection. A fuel injection system in which each cylinder is individually fueled.
MDP -- Manifold Differential Pressure
MIL -- Malfunction Indicator Lamp
MST -- Manifold Surface Temperature
NVRAM -- Non-Volatile RAM. Memory which retains information typically via an internal battery.
5
O2S -- Oxygen Sensor
OBD -- On Board Diagnostic. A system that monitors some or all computer input and control signals.
Signal(s) outside a predetermined range imply a fault in the system or a related system.
OC -- Oxidation Catalytic Converter. A catalytic converter system that reduces HC and CO.
OL -- Open Loop. An operating mode based on programmed values and not modified by a feedback
system.
OSS -- Output Shaft Speed

P Through S Acronyms

PCM -- Powertrain Control Module
PCV -- Positive Crankcase Ventilation
PNP -- Park Neutral Position
PRNDL -- Automatic transmission gear selection lever. Park, Reverse, Neutral, Drive, Low
PROM -- Programmable Read Only Memory. A memory chip which can be programmed only one
time.
PSP -- Power Steering Pressure
PSPS -- Power Steering Pressure Switch
PTOX -- A system for lowering Diesel engine particulate emissions by collecting particulates and
periodically burning them through oxidation.
PWM -- Pulse Width Modulation. A method of proportionally controlling an actuator by varying the
on/off time of a rectangular waveform.
QDM -- Quad Driver Module. An electronic component that contains four output driver circuits.
RAM -- Random Access Memory. A memory which does not maintain its content when power is
removed.
RM -- Relay Module
ROM -- Read Only Memory. Memory which is programmed by the device manufacturer and whose
contents cannot be altered.
RPM -- Revolutions Per Minute
RWD -- Rear Wheel Drive
Sterm, Short Term -- Short Term Fuel Trim. The Short Term fuel correction factor that the PCM is
using.
SA -- Spark Advance. The crankshaft angle relative to TDC (generally) at which a spark event is
initiated.
SC -- Supercharger
6
SCB -- Supercharger Bypass
SRT -- System Readiness Test (applicable to OBD2 scan tool communications)
SFI -- Sequential Fuel Injection. A multiport fuel injection system in which each injector is individually
energized and timed relative to its cylinder intake event.
SR -- Spark Retard. The degrees of spark retard which have been subtracted form the nominal spark
advance value. Is generally caused by an engine knock condition.
SRI -- Service Reminder Indicator
SS -- Shift Solenoid
SIR -- Supplemental Inflatable Restraint (air bag)

T Through Z Acronyms

TAC -- Throttle Actuator Control
TBI -- Throttle Body Injection. An electronically controlled fuel injection system in which one or more
fuel injectors are located in a throttle body.
TC -- Turbocharger
TCC -- Torque Converter Clutch
TCCP -- Torque Converter Clutch Pressure
TCM -- Transmission Control Module
TDC -- Top Dead Center. The position of the crankshaft when the piston of interest is at the topmost
point of travel.
TFP -- Transmission Fluid Pressure
TFT -- Transmission Fluid Temperature
TR -- Transmission Range
TSS -- Turbine Shaft Speed
TRLHP -- Track Road Load Horsepower. The power required to maintain a vehicle at a constant
speed, taking into account power losses due to wind resistance, tire losses, bearing friction, etc.
TP -- Throttle Position
TPS -- Throttle Position Sensor
TFP -- Transmission Fluid Pressure
TVV -- Thermal Vacuum Valve. A valve that controls vacuum levels or routing based on temperature.
TWC -- Three Way Catalyst. A Catalytic converter system that reduces HC, NO and Nox.
VAF -- Volume Air Flow. A system that provides information on the volume flow rate of the intake air
to the engine.
7
VCM -- Vehicle Control Module
VCRM -- Variable Control Relay Module
VIN -- Vehicle Identification Number
WOT -- Wide Open Throttle. A mode of PCM operation that is dependent on the throttle being open
beyond a programmed percentage.
WU -- Warm Up

 

very nice,
thanks Daniel!
:hurray:

 

thats a prety good list

 

Wow! That's a pretty comprehensive list. I just printed it off for future reference. Nice job. :thumbs:

 

tanx, a lot :hurray: :hurray:

 

::):):):thumbs:

 

This is great! I have often wondered what some of the acronyms mean.

 

TALFTI Ithanks a lot for the info) :)

 

Thanks Daniel, pasted it into word a couple weeks ago :thumbs: I went looking for one in there today I didn't find though, CHP. I know RWHP and FWHP but :confused: I've been seeing this recently CFI-EFI usually reffering to it.

 

i belive that CHP i short for Combined Heat and Power....

CFi -- Continuos Fuel Injection. A fuel injection system whereby the injector flow is controlled by the
fuel pressure.


EFi Eletronic Fuel injection - used to control all modern car engines.

i hope the above is correct cus' i'm not 100% on them...




[Modified by Daniel DK, 9:53 AM 1/23/2004]

 

I may be in error, but I think CHP = Crank Horse Power = Flywheel Horse power. Different name for the same measurement.

 

:iagree: :yesnod:

 

Looks like the guest list at a convention of PHDs! :D

Thanks, great info!