Adapt Function

The 4L80-E transmission uses a line pressure control system, which has the ability to continuously adapt the system's line pressure. This compensates for normal wear and break in of the following parts:
- The clutch fiber plates
- The seals
- The springs

The VCM/PCM maintains the following adapt parameters for the transmission:
- Upshift Adapt-The VCM/PCM monitors the Automatic Transmission Input (Shaft) Speed Sensor (A/T ISS) and the Output Speed Sensor (OSS) during commanded shifts in order to determine if a shift is occurring too fast or too slow. The VCM/PCM adjusts the signal to the transmission pressure control solenoid valve in order to maintain a set shift feel.
- Steady State Adapt (Diesel only)-The PCM monitors the Automatic Transmission Input (Shaft) Speed Sensor (A/T ISS) and the Output Speed Sensor (OSS) after a shift in order to calculate the amount of slippage in that gear. The PCM then adjusts the signal to the Transmission Pressure Control Solenoid signal in order to maintain slippage below a set amount.

Reset the Transmission Adapt functions when the transmission is overhauled or replaced. To reset the Transmission Adapt functions, use the Scan Data tool.