Yes ,don't know which transmission you have ,4L80-E or 4L60-E but both are controlled by the PCM - powertrain control module .
The 4L80-E is a fully automatic rear wheel drive electronically controlled transmission. The 4L80-E provides four forward ranges, including overdrive and reverse. A gear type of oil pump controls shift points. The powertrain control module (PCM) and the pressure control (PC) solenoid, force motor, regulate these shift points. The PCM also controls shift schedules and TCC apply rates. Transmission temperature also influences shift schedules and TCC apply rates.
The 4L60-E transmission utilizes a line pressure control system during upshifts to compensate for the normal wear of transmission components. By adjusting the line pressure, the PCM can maintain acceptable transmission shift times. This process is known as "adaptive learning" or "shift adapts" and is similar to the closed loop fuel control system used for the engine.
Do not, under any circumstances, attempt to diagnose a powertrain condition without basic knowledge of this powertrain. If you perform diagnostic procedures without this basic knowledge, you may incorrectly diagnose the condition or damage the powertrain components.
You must be familiar with some basic electronics in order to use this section of the service manual. You should also be able to use the following special tools:
A digital multimeter (DMM)
A circuit tester
Jumper wires or leads
A line pressure gage set