PARK Mode
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
While the transmission is in PARK, with the engine idling, FastLearn will cycle through a series of tests where the 3rd, 5th and reverse clutch and the 2nd clutch is repeatedly applied to learn their clutch characteristics. During the 3rd, 5th and reverse clutch and 2-6 clutch apply/release procedure, FastLearn is able to characterize the pressure control solenoid 1 (PCS1) and pressure control solenoid 2 (PCS2) pressures corresponding to clutch return springs, and is also able to learn the volumes for the 3rd, 5th and reverse clutch and 2-6 clutch packs. In addition, the low and reverse clutch is repeatedly applied and released in PARK to purge out air for later learning of the clutch volume.