Low transmission fluid level
Dirty transmission fluid
Faulty Control Solenoid Valve Assembly
Control Solenoid Valve Assembly harness or connectors
Control Solenoid Valve Assembly circuit is open or shorted
Faulty Transmission Control Module (TCM)
Engine Light ON (or Service Engine Soon Warning Light)
The transmission fluid pressure switch, also known as the pressure switch manifold, is a multiple switch assembly made up of 3 normally open pressure switches and 1 normally closed pressure switch. Pressure switch 1 monitor shift valve 1 positioning, pressure switch 2 monitors shift valve 2 positionings, and pressure switch 3 monitors shift valve 3 positionings. The normally open pressure switches 1–3 communicate the positioning to the transmission control module (TCM). The position of shift valves 1–3 is controlled by 3 normally closed shift solenoid valves. When energized, the shift solenoid valves directly control the main pressure to shift valve 1, 2, or 3, which strokes the shift valve. When the valve is stroked, an exhaust passage is blocked and fluid pressure to the pressure switch increases. The Diagnostic Trouble Code (DTC) will be set if the shift solenoid 3 is commanded off and pressure switch 3 remains on for 6–10 s, depending on the transmission fluid temperature.