Abbreviations and Their Meanings
THROTTLE POSITIONSMinimum Throttle: The least amount of throttle opening required for an upshift.
Light Throttle: Approximately 1/4 of accelerator pedal travel.
Medium Throttle: Approximately 1/2 of accelerator pedal travel.
Heavy Throttle: Approximately 3/4 of accelerator pedal travel.
Wide Open Throttle (WOT): Full travel of the accelerator pedal.
Full Throttle Detent Downshift: A quick apply of the accelerator pedal to its full travel, forcing a downshift.
Zero Throttle Coastdown: A full release of the accelerator pedal while the car is in motion and in drive range.
Engine Braking: A condition where the engine is used to slow the car by manually downshifting during a zero throttle coastdown.
SHIFT CONDITIONS
Bump: A sudden and forceful apply of a clutch or a band.
Chuggle: A bucking or jerking. This condition may be most noticeable when the converter clutch is engaged. It is similar to the feel of towing a trailer.
Delayed: A condition where a shift is expected but does not occur for a period of time. This could be described as a clutch or band engagement that does not occur as quickly as expected during a part throttle or wide open throttle apply of the accelerator, or during manual downshifting to a lower range. This term is also defined as LATE or EXTENDED.
Double Bump (Double Feel): Two sudden and forceful applies of a clutch or a band.
Early: A condition where the shift occurs before the car has reached proper speed. This condition tends to labor the engine after the upshift.
End Bump: A firmer feel at the end of a shift than at the start of the shift. This is also defined as END FEEL or SLIP BUMP.
Firm: A noticeably quick apply of a clutch or band that is considered normal with a medium to heavy throttle. This apply should not be confused with HARSH or ROUGH.
Flare: A quick increase in engine RPM along with a momentary loss of torque. This most generally occurs during a shift. This condition is also defined as SLIPPING.
Harsh (Rough): A more noticeable apply of a clutch or band than FIRM. This condition is considered undesirable at any throttle position.
Hunting: A repeating quick series of upshifts and downshifts; that causes a noticeable change in engine RPM, such as a 4-3-4 shift pattern. This condition is also defined as BUSYNESS.
Initial Feel: A distinctly firmer feel at the start of a shift than at the finish of the shift.
Late: A shift that occurs when the engine's RPM is higher than normal for a given amount of throttle.
Shudder: A repeating jerking condition similar to CHUGGLE but more severe and rapid. This condition may be most noticeable during certain ranges of car speed.
Slipping: A noticeable increase in engine RPM without a car speed increase. A slip usually occurs during or after initial clutch or band apply.
Soft: A slow, almost unnoticeable clutch or band apply with very little shift feel.
Surge: A repeating engine related condition of acceleration and deceleration that is less intense than CHUGGLE.
Tie-Up: A condition where two opposing clutch and/or bands are attempting to apply at the same time causing the engine to labor with a noticeable loss of engine RPM.
NOISE CONDITIONS
Drive Link Noise: A whine or growl that increases or fades with engine RPM. This noise is most noticeable under a light throttle acceleration, or in Park or Neutral with the car stationary,
Final Drive Noise: A hum related to car speed. This noise is most noticeable under a light throttle acceleration or zero throttle coastdown.
Planetary Gear Noise: A whine related to car speed. This noise is most noticeable in First gear, Second gear, Fourth gear, or Reverse. The condition becomes less noticeable after an upshift.
Pump Noise: A high pitched whine that increases with engine RPM and may be affected by modulated line pressure boost.
TRANSMISSION ABBREVIATIONS
A/C: Air Conditioning
A/T ISS Sensor: Automatic Transmission Input (Shaft) Speed Sensor
AC: Alternating Current
CKT: Circuit
DC: Direct Current
DLC: Diagnostic Link Connector
DTC: Diagnostic Trouble Code
ECT Sensor: Engine Coolant Temperature Sensor
MAP: Manifold Absolute Pressure
MIL: Malfunction Indicator Lamp
NC: Normally Closed
NO: Normally Open
0BD: On Board Diagnostic
PCM: Powertrain Control Module
PC Sol. Valve: Pressure Control Solenoid Valve
PM: Permanent Magnet
PWM: Pulse Width Modulation
RPM: Revolutions Per Minute
TCC Sol. Valve: Torque Converter Clutch Solenoid Valve
TFP Val. Position Sw.: Automatic Transmission Fluid Pressure Manual Valve Position Switch
TFT: Automatic Transmission Fluid Temperature
TP Sensor: Throttle Position Sensor
VSS Assy.: Vehicle Speed Sensor Assembly
WOT: Wide Open throttle