When the gear selector lever moves to the Neutral (N) position from the Reverse (R) position, the following changes to the hydraulic and the electrical systems in the transmission occur:

Manual Valve

Mechanically controlled through the gear selector lever, the manual valve directs line pressure into the PRND43 and the PRND4 circuits. PRND4 fluid then passes around a valve land and enters the PRN fluid passage.

Automatic Transmission Manual Valve Position Switch

Reverse fluid pressure exhausts at the manual valve. This action allows the reverse pressure switch to open its circuit to the PCM.

Internal Mode Switch (IMS)

The internal mode switch (IMS) is a sliding contact electrical switch assembly that corresponds to the PRNDL position selected. Each of the PRNDL positions has a unique ground pattern on the four wires from the PCM. The IMS consists of two major components: The housing, which houses the tracks and makes up the stationary contacts. The Insulator assembly makes up the moving contacts and is linked to the detent lever. The range detection is accomplished by securing the moving contacts of the IMS to the detent lever. When the driver selects a PRNDL position, the detent lever inside the transaxle rotates. This slides the IMS moving contacts which in return grounds the four wires in a unique pattern for each gear selection corresponding to the PRNDL position selected. The IMS is electrically connected by five wires (four of which the PCM supplies voltage to and one wire that is a common ground) to the transaxle pass through connector.