Transmission Range Pressure Switches

Transmission Range Pressure Switches & Trans Temperature Sensor Circuits:

DESCRIPTION
The transmission range pressure switch assembly is a set of five pressure operated switches (two normally closed and three normally open), that detect fluid pressure conditions with the valve body passages. The five switches are connected in three signal circuits ("A", "B", and "C") and arranged in such a way that the different combinations of "ON" and "OFF" states on the three signal lines describe what gear the transmission is actually in.

OPERATION
The PCM applies a reference voltage to each of the three signal circuits and then monitors the voltage in the circuits. If the switches are closed to ground on a circuit, the voltage signal goes "LOW", describing an "ON" state for that circuit.

Possible combinations of logic states ("ON" or "OFF") are listed below for the different transmission ranges. A grounded circuit is an "ON" state (voltage "LOW"). An open circuit is an "OFF" state (voltage "HIGH").

CIRCUIT "A" "B" "C"
_________________________
PARK OFF ON OFF
REVERSE ON ON OFF
NEUTRAL OFF ON OFF
D4 OFF ON ON
D3 OFF OFF ON
D2 OFF OFF OFF
D1 ON OFF OFF

NOTE: The combinations listed below are NOT possible unless a malfunction is present. There is no selectable range that would cause these logic states.

CIRCUIT "A" "B" "C"
_________________________
ON OFF ON
ON ON ON