Transmission Adaptive Functions

Transmission Adaptive Functions

The 4T45-E automatic transmission uses a line pressure control system, which has the ability to continuously adapt the system line pressure. This compensates for normal wear of the following parts:

* The clutch fiber plates
* The seals
* The springs


The powertrain control module (PCM)/transmission control module (TCM) maintains the Upshift Adapt parameters for the transmission. The PCM/TCM monitors the input speed sensor (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 PCM/TCM adjusts the signal from the transmission pressure control (PC) solenoid in order to maintain a set shift feel.


Transmission adapts must be set again when the transmission is overhauled or replaced. In order to set the transmission adapts again, select the following:

1. Scan Tool
2. Transmission/Transaxle
3. Special Functions
4. Reset Transmission Adapts