Circuit/System Description
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The transmission fluid pressure (TFP) switch 5 is part of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The TCM supplies 12 volts to the TFP switch 5 on the TFP switch 5 signal circuit. The TFP switch 5 has an internal case ground. TFP switch 5 is normally closed, Low. When oil pressure is present at the TFP switch 5, the switch is open, high. The normally low clutch pressure control (PC) solenoid 4 controls the transmission fluid to the 1-2-3-4 clutch. The TCM monitors the normally closed TFP switch 5 signal circuit to determine the 1-2-3-4 clutch status.