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 VCM/PCM monitors the A/T ISS and the OSS after a shift in order to calculate the amount of slippage in that gear. The VCM/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.