Q: How does the range sensor prevent accidental movement during engine cranking, and How to test, adjust, or replace it on Nissan Quest?
A: The range sensor prevents accidental movement caused by engine cranking with the shift selector in reverse or forward gears, as it is wired in series with the starter relay, allowing the starter motor to crank only when the transaxle is in Park or Neutral. To test the transaxle range sensor, disconnect the electrical connectors, which include an 8-pin connector and a 2-pin connector that governs the starter circuit. Move the shift lever into each position and check for continuity between the indicated terminals; if continuity isn't as designated, attempt to adjust the switch, and if adjustment fails, replace the switch. For adjustment, raise the vehicle securely on jackstands, remove the splash shield, shift the selector lever into Neutral, and remove the shift cable lock nut on the range sensor linkage arm. Loosen the switch mounting bolts slightly, insert a drill bit through the hole in the lever into the alignment hole in the range sensor, then tighten the mounting bolts to the specified torque. Ensure continuity exists on the designated terminals before reinstalling the shift cable, reversing the removal process. For replacement, raise the vehicle securely, disconnect the range sensor electrical connectors, place the shift lever in Neutral, and remove the mounting bolts for the transaxle range sensor. Install the new switch onto the control shaft, ensuring it remains in Neutral while tightening the bolts, then adjust the range sensor as previously described, confirming that the engine starts only when the shift lever is in Neutral or Park.