Transaxle Range Switch

The transaxle range switch determines which gear position has been manually selected. The PCM determines this gear selection by detecting a combination of opens and grounds at the four switch (A, B, C and D) inputs of the transaxle range switch. When a switch is open, the PCM code input will be high (near ignition voltage). When the switch is closed, the PCM code input will be low (0 volts). The specific combinations of highs and lows (opens and grounds at switch) for the four code inputs at the PCM denote which gear position has been selected. Only one combination is possible for each manual gear selected. The PCM uses the gear selection to determine which gear to command On and how much main line pressure needed to hold the gear being selected.