Circuit/System Description
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.
The transmission fluid pressure (TFP) switch 3 is part of the control solenoid (w/body and TCM) valve assembly and has no seviceable parts. The TCM supplies 12 volts to the TFP switch 3 on the TFP switch 3 signal circuit. The TFP switch 3 has an internal case ground. TFP switch 3 is normally closed, Low. When oil pressure is present at the TFP switch 3, the switch is Open, High. The normally low clutch pressure control (PC) solenoid 4 controls the transmission fluid to the 2-6 clutch. The TCM monitors the normally closed TFP switch 3 signal circuit to determine the 2-6 clutch status.