WTEC III ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL DEFINITIONS AND ABBREVIATIONS 2–4. ABBREVIATIONS (cont’d) OL O ver L imit or O il L evel — For O ver L imit see “ ”. Indicates O il L evel is being displayed on a shift selector. OLS O il L evel S ensor — Electronic device (optional) on control module for indicating transmission fluid level. PCCS P ROM C alibration C onfigurator S ystem PCMCIA ssociation — Memory device for use with Pro-Link ® containing Allison Transmission programming and diagnostics. P ersonal C omputer M emory C ard I nternational A PROM P rogrammable R ead O nly M emory PSS P rimary S hift S elector — Main shift selector in a two-selector control system.
PTO P ower T ake o ff PWM Solenoid P ulse W idth M odulated Solenoid — Solenoids are controlled by pulse width modulation. Solenoid control of clutch pressures is based on the solenoid’s duty cycle. Duty cycle is determined by the ratio of solenoid’s on-time to off-time. RMR R etarder M odulation R equest — Signal from a retarder control device. RPR R eturn to P revious R ange — Diagnostic response in which the transmission is commanded to return to previously commanded range. SCI S erial C ommunication I nterface — Used to transmit data and messages between the diagnostic tool and the ECU and other systems such as electronically-controlled engines.
SOL OFF All SOL enoids OFF SPI S erial P eripheral I nterface — The means of communication between the microprocessor and the interface circuits. SSS S econdary S hift S elector — Alternate shift selector in a two-selector control system. TID T rans ID — A feature which allows the ECU to know the transmission configuration and provide the corresponding calibration required. TPS T hrottle P osition S ensor — Potentiometer for signaling the position of the engine fuel control lever. V V ersion — Abbreviation used in describing ECU software levels.
VDC V olts D irect C urrent (DC) VIM V ehicle I nterface M odule — A watertight box containing relays and fuses — interfaces the transmission electronic control system with components on the vehicle. VIW V ehicle I nterface W iring — Interfaces ECU programmed input and output functions with the vehicle wiring. Volt Unit of electrical force. VOM V olt/ o hm m eter WOT W ide O pen T hrottle WT W orld T ransmission Infinity — Condition of a circuit with higher resistance than can be measured, effectively an open circuit. Copyright © 1999 General Motors Corp.