So if it's non-operational then it's always reading open, meaning the PCM might think it's always in gear. (just noticed you said the same at the end)
Interestingly though, when coasting (pedal depressed but shifter in-gear) the engine would often idle high while moving until come to a complete stop. In the past I had assumed this was to help gaurd against user-error... failing to match RPMs with vehicle speed before releasing the clutch pedal. But it wouldn't do this all the time. Often it would idle back down regardless of movement. Haven't paid enough attention to figure out why it sometimes idles high until stop consistently, and others, idles at 800-1000RPM consistently while still moving. Lately I've noticed a low idle regardless of movement/non-movement.
I'd rather use my brakes for braking (they're designed for it) than my trans+engine so I do coast (braking intermittently) down a long steep decline near my home. Even with the trans in gear and engaged I'd still have to brake anyway; just not as often. Nothing to do with fuel economy in my case and still all original front hardware at ~236k. (except for pads+rotors of course) Only just very recently replaced rear wheel cylinders (one leaked) and still original drums. Would rather save engine/gear wear. Mistake many people make is riding the brakes and/or using "lifetime" pads. Heat is the single biggest factor. 2-3 second pulses are all that is necessary. Want to maintain below 50 then periodically slow down to 40 and allow up to 55mph. (accounting for presence/non-presence of following traffic of course) Disengaging the clutch for short or minor downgrades is excessive and wouldn't go to neutral with an automatic at all unless it had known transmission problems.
Also interesting, drove a '96 Saturn SC2 model with an automatic transmission that would automatically downshift if it detected you braking to maintain speed on a decline.