Glossary of Terms
4EAT: 4-Speed Electronic Automatic Transaxle.
4X4L: 4X4 Low input switch.
A4LD: Automatic 4-Speed Lock-up-converter Drive.
A/C: Air Conditioning.
ACC: A/C Clutch Compressor signal input to the EEC-IV processor relating status of the A/C clutch.
ACCS: A/C Cycling Switch.
A/C P: A/C Pressure Cut-out switch.
A/C DV: Air Cleaner Duct and Valve motor.
ACL: Automatic Adjustable Shock Controller.
A/CL BIMET: Air Cleaner Bimetal sensor.
ACD: Air Conditioner Demand switch.
ACT: Air Charge Temperature sensor or its signal circuit.
ACV: (Thermactor) Air Control Valve.
AHFSS: Air Condition/Heater Function Select Switch input to the EEC-IV processor relating status of the A/C heater function select switch.
AIR BPV: (Thermactor) Air Bypass Valve.
AM1: Thermactor Air Management 1 (TAB).
AM2: Thermactor Air Management 2 (TAD).
AMBIENT TEMPERATURE: Temperature of air surrounding an object e.g., temperature where vehicle is being worked on.
AOD: Automatic Overdrive.
ANTI-BFV: Anti-Backfire Valve.
A/T: Automatic Transmission.
ATDC: After Top Dead Center.
AVOM: Analog Volt-Ohm Meter.
AXOD: Automatic Transaxle Overdrive.
AXOD-E: Automatic Transaxle Overdrive, Electronically Controlled.
BASE IDLE: Idle RPM determined by throffle lever hardset on throttle body while Idle Speed Control is fully retracted and disconnected.
BATT: Battery
BATT(+): Battery positive post or its circuit.
BATT(-): Baftery negative post or its circuit.
BOB: (Breakout Box) An EEC-IV test device which connects in series with the processor and the EEC-IV harness and permits measurements of processor inputs and outputs.
BOO: Brake On-Off input to the EEC-IV processor indicating a braking drive mode.
BP: Barometric Pressure sensor or its signal circuit.
BPA: By-Pass Air Solenoid. Used to control idle speed on EFI and SEFI vehicles.
BREAKOUT BOX: A service tool that "tees" in-between the EEC-IV processor and the 60-pin harness connector. The breakout box contains 60 test pins that can be probed for EEC-IV testing.
BTDC: Before Top Dead Center.
BV: Bowl Vent (Carburetor Fuel Bowl)
BVT: Back Pressure Variable Transducer.
CANP: Canister Purge solenoid or its control circuit.
CSE GND: Case Ground (EEC-IV processor case).
CATALYST: A muffler-like device in the exhaust system containing a monolithic substrate (a ceramic honeycomb structure) that is coated with catalytic metals such as platinum or palladium. When hot exhaust gases come in contact with these metals a chemical reaction takes place to consume unburned hydrocarbon, carbon monoxide and nitrous oxides.
CBD: Closed Bowl Distributor. With this design, the TFI-IV module is electrically connected to the distributor thru a harness connector, not a direct plug in connection.
CCC: Converter Clutch Control solenoid or its control circuit.
CCD: Computer Controlled Dwell.
CCO: Converter Clutch Override output from the EEC-IV processor to the transmission.
CCS: Coast Clutch Solenoid or its control circuit.
CES: Clutch Engage Switch.
CFI: Central Fuel Injection. A computer controlled fuel metering system which sprays atomized fuel into a throttle body mounted atop the intake manifold.
"CHECK ENGINE" OR "SERVICE ENGINE SOON" LIGHT: A dash panel light used either to aid in the identification and diagnosis of EEC system problems or to indicate that maintenance is required on non-EEC equipped vehicles.
CID: Cylinder Identification sensor or its signal circuit.
CLC: Converter Lock-up Clutch.
CLUTCH: Clutch engagement switch or its control circuit.
COC: Conventional Oxidation Catalyst.
COMPUTED TIMING: The total spark advance in degrees before top dead center. Calculated by the EEC-IV processor based on input from a number of sensors.
CONTINUOUS SELF-TEST: A continuous test of the EEC-IV system conducted whenever the vehicle is in operation.
CURB IDLE: Computer controlled Idle rpm.
CWM: Cold Weather Modulator.
DCL: Data Communications Link.
DFS: Decel Fuel Shut-off.
DIS: Distributorless Ignition System (low data rate).
DOL: Data Output Link. Fuel calculation data from the EEC-IV processor to the electronic tripminder.
DPDIS: Dual Plug Distributorless Ignition System.
DPH: Dual Plug Head.
DPI: Dual Plug Inhibit.
DV: Delay Valve.
DVOM: Digital Volt-Ohm Multimeter that displays voltage or resistance measurements in digital form on a liquid crystal display (LCD).
DV TW: Delay Valve Two-Way.
EATC: Electronic Automatic Temperature Control.
E40D: Electronic 4-Speed Overdrive transmission.
ECA: Electronic Control Assembly.
ECT: Engine Coolant Temperature sensor or its signal circuit.
EDF: Electro-Drive Fan relay or its control circuit.
EDIS: Electronic Distributorless Ignition System (high data rate).
EEC: Electronic Engine Control. A computer controlled system of engine control.
EEGR: Electronic EGR Valve (Sonic).
EFI: Electronic Fuel Injection. A computer controlled fuel system that distributes atomized fuel through an injector located in each intake port of the engine. The fuel injectors are fired using bank-to-bank circuitry.
EGO: Exhaust Gas Oxygen sensor or its signal circuit.
EGOG: EGO Ground.
EGR: Exhaust Gas Recirculation system designed to allow the flow of inert exhaust gases into the combustion chamber to cool the combustion and thus reduce nitrous oxides in the exhaust.
EGR S/O: EGR Shut Off.
EGRC: EGR Control vacuum solenoid valve or its control circuit.
EGRV: EGR Vent vacuum solenoid valve or its control circuit.
EHC: Exhaust Heat Control vacuum solenoid valve or its control circuit.
ENGINE RUNNING SELF-TEST: A test of the EEC-IV system conducted with the engine running and the vehicle at rest.
EPC: Electronic Pressure Control (used in E40D transmissions).
ER: Engine Running Self-Test (same as KOER).
ERS: Engine rpm Sensor or its signal circuit.
EVP: EGR Valve Position sensor or its signal circuit.
EVR: EGR Vacuum Regulator solenoid or its control circuit.
FBC: Feedback Carburetor. An MCU controlled fuel system employing a stepper motor or a dithering solenoid that controls fuel/air mixture by bleeding air into the main and idle systems of the Carburetor.
FCS: Fuel Control Solenoid or its control circuit.
Fl: Fuel Injector or its control circuit.
FIPL: Fuel Injection Pump Lever sensor or its signal circuit.
FLC: Fluid Lock-Up Conveder.
FMEM: Failure Mode Effects Management. This alternative strategy protects vehicle function from adverse effects of an EEC component failure.
FP: Fuel Pump relay or its control circuit.
FPM: Fuel Pump Monitor. A circuit in the EEC system used to monitor the electric fuel pump operation on some EEC-IV equipped vehicles.
FTO: Filtered Tach Output. An output from the DIS TFI-IV module which provides a filtered ignition signal to the processor in order to control dwell.
FUEL RICH/LEAN: A qualitative evaluation of air/fuel ratio based on an A/F value known as stoichiometry or 14.7. In the EEC-IV system rich/lean is determined by a voltage signal from the EGO sensor. An excess of oxygen (lean) is an EGO voltage of less than .4 volts, a rich condition is indicated by an EGO voltage of greater than .6 volts.
FWD: Front Wheel Drive.
GND or GRND: A common ground circuit for all vehicle power.-
GOOSE: A brief openning and closing of the throftle.
HALL EFFECT: A process where current is passed through a small slice of semiconductor material at the same time as a magnetic field to produce a small voltage in the semi-conductor.
HBV: Heater Blower Voltage input to the EEC-IV processor reflecting heater blower voltage demand.
HEDF: High speed Electro-Drive Fan relay or its control circuit.
HEGO: Heated EGO pensor or its signal circuit.
HEGOG or HEGO GND: Heated EGO Ground.
HIC: Hot Idle Compensator.
HLOS: Hardware Limited Operation Strategy. Certain types of computer malfunctions will place the EEC-IV processor into H LOS mode. Output commands are replaced with fixed values.
HO: High Output.
HSC: High Swirl Combustion.
IAS: Inlet Air Solenoid valve or its control circuit.
IBP: Integral Back Pressure.
IDLE LIMITER: A device to control minimum and maximum idle fuel richness. The idle limiter is intended to prevent unauthorized persons from making overly rich idle adjustments.
IDM: Ignition Diagnostics Monitor. A continuous monitor of the ignition input to the EEC-IV processor used to detect intermittent ignition faults.
IGN: Ignition circuit or system.
INJ: Injector (Fuel).
INJ GND: Injector Ground (Fuel).
IRCM: Integrated Relay Control Module.
ISC: Idle Speed Control. Currently there are two types of computer controlled idle speed
control: DC motor ISC and air bypass ISC.
ITR: In-Tank Reservoir.
ITS: Idle Tracking Switch. Used on CFI vehicles to inform EEC if the throttle is in contact with the DC motor.
KAM: Keep Alive Memory. A series of vehicle battery powered memory locations in the microprocessor which allows the microprocessor to store input failures identified during normal operation for use in later diagnostic routines and adapts some calibration parameters to compensate for changes in the vehicle system.
KAPWR: Keep Alive Power.
KEY ON ENGINE RUNNING SELF-TEST:
A test of the EEC-IV system conducted with power applied and the engine at rest.
KOEO: Key On Engine Off Self-Test.
KOER: Key On Engine Running Self-Test (same as Engine Running (ER) Self-Test).
KS: Knock Sensor or its signal circuit.
L: Liters.
LUS: Lock Up Solenoid.
MA or MAF: Mass Air Flow Sensor or its signal circuit.
MAP: Manifold Absolute Pressure sensor or its sigrial circuit.
MCU: Microprocessor Control Unit.
MECS: Mazda Equipped Control System.
MIL: (Malfunction Indicator Light) An electric circuit between the EEC-IV processor and the "CHECK ENGINE" or "SERVICE ENGINE SOON" light on the dash panel of EEC-equipped vehicles.
MLP: Manual Lever Position sensor or its signal circuit.
MONITOR BOX: An optional EEC-IV test device which connects in series with the EEC-IV processor and its harness, and permits measurements in various units of processor inputs and outputs.
M/T: Manual Transmission
NDS: Neutral Drive Switch or its signal circuit.
NGS: Neutral Gear Switch or its signal circuit.
NPS: Neutral Pressure Switch or its signal circuit.
OASIS: On-line Automobile Service Information System.
OCC: Output Circuit Check.
0CIL: Overdrive Cancel Indicator Light.
0CS: Overdrive Cancel Switch.
OCT ADJ: Octane Adjust device which modifies spark advance.
OHC: Overhead Cam.
OPEN CIRCUIT: A circuit which does not provide a complete path for the flow of current.
OSC: Output State Check.
OVERLAY CARD: A plastic card used with the Monitor box to identify EEC-IV signals for each engine. The card also programs the monitor for auto mode measurements.
PCV: Positive Crankcase Ventilation. A system which controls the flow of crankcase vapors into the engine intake manifold where they are burned in combustion rather than being discharged into the atmosphere.
PFE: Pressure Feedback EGR sensor or its signal circuit.
PIP: Profile Ignition Pickup. A "hall effect" vane switch that furnishes crankshaft position data to the EEC-IV processor.
PROCESSOR: EEC-IV Electronic Control Assembly.
PSPS: Power Steering Pressure Switch. An EEC-IV processor input to regulate idle speed based on power steering load demand.
PULSE AIR SYSTEM: Part of the emission control system that utilizes a reed-type check valve which allows air to be drawn into the exhaust system as a result of exhaust pulses.
PVS: Ported Vacuum Switch.
PWR GND: Power Ground.
OUICK TEST: A functional diagnostic test of the EEC system consisting of vehicle preparation and hookup, Key On Engine Off, Engine Running and Continuous SelfTests.
RECORDER: An optional EEC-IV test device which works jointly with the Monitor box. It allows up to 8 EEC-IV signals to be electronically recorded over a 50 second period.
RELAY: A switching device operated by a low current circuit which controls the opening and closing of another circuit of higher current capacity.
RELIEF VALVE: A pressure limiting valve located in the exhaust chamber of the thermactor air pump. It functions to relieve part of the exhaust airflow if the pressure exceeds a calibrated value.
RWD: Rear Wheel Drive.
SAW: Spark Angle Word. Timing information sent from EEC-IV to the EDIS module. This information is used by the EDIS module to calculate final ignition timing.
SBS: Supercharger Bypass Solenoid or its control circuit.
SC: Super Charged.
SDV: Spark Delay Valve.
SEFI: Sequential Electronic Fuel Injection. A computer controlled fuel system that distributes atomized fuel through an injector located in each intake port of the engine. Each injector is fired separately and has individual circuits.
SELF-TEST: One of three subsets of the
EEC Quick Test: Key On Engine Off, Engine Running, and Continuous.
SHO: Super High Output.
SHORT CIRCUIT: An undesirable connection between a circuit and any other point.
SIG RTN: Signal Return circuit for all sensor signals except HEGO.
SIL: Shift Indicator Light. A system that provides a visual indication to the driver of a vehicle when to shift to the next higher gear to obtain optimum fuel economy.
SOLENOID: A wire coil with a moveable core that changes position by means of electro-magnetism when current flows through the coil.
SPOUT: Spark Output Signal from the EEC-IV processor.
SS l: Shift Solenoid 1 or its control circuit.
SS2: Shift Solenoid 2 or its control circuit.
SS 3/4-4/3: (Shift Solenoid 3/4-4/3) Output from the EEC-IV processor to the transmission that selects 3rd and 4th gears.
STAR: Self-Test Automatic Readout. A testing device in which the EEC and MCU systems output service codes in a digital format.
STI: Self Test Input circuit in the EEC and MCU systems used to initiate Self-Test.
STO: Self Test Output circuit in the EEC and MCU systems that transmits service codes (pulses) to either a VOM or STAR tester. .
TAB/TAD: Thermactor Air Bypass/ Thermactor Air Diverter vacuum solenoid valves or their control circuits.
TCP: Temperature Compensated (Acceleration) Pump.
TFI: Thick Film Ignition. An ignition module comprised of a custom integrated circuit, Darlington output device and associated thick film integrated components.
TGS: Top Gear Switch. A lock out mechanism that prevents the SIL from lighting when the vehicle is in top gear.
THERMACTOR: A system for injection of air into the exhaust system to aid in the control of hydrocarbon and carbon monoxides in the exhaust.
THERMACTOR Ii: See Pulse Air System.
THS: Transmission Hydraulic Switch. An input to the processor that indicates the occurance of a shift between specific gears.
THS 3/2: Transmission Hydraulic Switch 3rd/2nd gear.
THS 4/3: Transmission Hydraulic Switch 4th/3rd gear.
TIMING: Relationship between spark plug firing and piston position usually expressed in crank shaft degrees before (BTDC) or after (ATDC) top dead center of the compression stroke.
TIV: Thermactor Idle Vacuum Valve.
TK: Throttle Kicker vacuum solenoid valve or its control circuit.
TOT: Transmission Oil Temperature Sensor or its signal circuit.
TP: Throttle Position sensor or its signal circuit.
TSP: Throttle Solenoid Positioner.
TTS: Transmission Temperature Switch.
TVS: Temperature Vacuum Switch.
TVV: Thermal Vent Valve, TWC: Three Way Catalyst.
VAF: Vane Air Flow sensor or its signal circuit.
VAT: Vane Air Temperature sensor or its signal circuit.
VBAT: Vehicle Battery voltage.
VCK-V: Vacuum Check Valve.
VCV: Vacuum Control Valve.
VDV: Vacuum Delay Valve.
VM: Vane Meter.
VOM: Volt-Ohm Meter used to measure voltage and resistance. Readings are indicated by sweep hand on a printed scale rather than a digital display.
VOTM: Vacuum Operated Throttle Modulator.
VPWR: Vehicle Power supply voltage regulated to 10-14 volts.
VR/S: Vacuum Regulator/Solenoid.
VRDV: Vacuum Retard Delay Valve.
VREF: Reference voltage supplied by the EEC-IV processor to some sensors and regulated to 4-6 volts.
VRESER: Vacuum Reservoir.
VREST: Vacuum Restrictor.
VR or VRS: Variable Reluctance Sensor. A non-contact transducer that converts mechanical motion into electrical control signals.
VRV: Vacuum Regulator Valve.
VSC: Vehicle Speed Control sensor or its signal circuit.
VSS: Vehicle Speed Sensor or its signal circuit.
VVA: Venturi Vacuum Amplifier.
VVC: Variable Voltage Choke relay or its control circuit.
VVV: Vacuum Vent Valve.
WAC: Wide-open throttle A/C Cutoff.
WOT: Wide-Open Throttle.