WTEC III ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL DEFINITIONS AND ABBREVIATIONS 2–4. ABBREVIATIONS A/N A ssembly N umber ABS A nti-lock B rake S ystem — OEM-provided means to detect and prevent wheel stoppage to enhance vehicle handling. Retarder and engine brakes will not apply when ABS is active. Amp Unit of electrical current. ATDT TM A llison T ransmission D iagnostic T ool — A software-based system for troubleshooting and maintaining electronic controls. C3PS witch — Pressure switch to signal the presence or absence of pressure in the C3 clutch-apply circuit.
C3 P ressure S CAN C etwork — A network for all SAE J1939 communications in a vehicle (engine, transmission, ABS, etc.) ontroller A rea N COP roperly — Hardware protection which causes the ECU to reset if software gets lost. C omputer O perating P CT C losed T hrottle DDR D eader — Diagnostic tool; most current version is the Pro-Link ® 9000 made by MicroProcessor Systems, Inc. Used to interrogate the ECU for diagnostic information and for reprogramming I/O packages in a calibration. iagnostic D ata R DNA D oes N ot A dapt — Adaptive shift control is disabled.
DNS D O N OT S HIFT — Refers to the DO NOT SHIFT diagnostic response during which the CHECK TRANS light is illuminated and the transmission will not shift and will not respond to the Shift Selector. DVOM D igital v olt/ o hm m eter ECU E lectronic C ontrol U nit (also commonly referred to as the “computer”) GPI G nput — Input signal to the ECU to request a special operating mode or condition. eneral P urpose I GPO utput — Output signal from the ECU to control vehicle components (such as PTOs, backup lights, etc.) or allow a special operating mode or condition. G eneral P urpose O J1587 Engine/transmission serial data communications link.
J1939 High-speed vehicle serial data communications link. LED L ight- E mitting D iode — Electronic device used for illumination. NNC N eutral N o C lutches — Neutral commanded with no clutches applied. NVL ow — The ECU has sensed turbine speed below 150 rpm when output speed is below 100 rpm and engine speed is above 400 rpm when N eutral V ery L (Neutral) was selected. This is usually caused by a dragging C1 or C3 clutch or a failed turbine speed sensor. NVL is attained by turning D solenoid “ON” (in addition to E solenoid) and the C4 and C5 clutches are applied to lock the transmission output. N OEM O riginal E quipment M anufacturer — Maker of vehicle or equipment.
Ohm Unit of electrical resistance. Copyright © 1999 General Motors Corp.