OBD test results are OD light steady on = PNP switch, OD switch, TCM. I'm leaning PNP switch - it's mechanical, exposed to heat + environment, and more prone to failure. OD switch maybe. TCM - 31036-3Y161 is NLA. (only reman) The one thing I don't see much discussion about is fluid types. I am using Castrol Transmax Import. I've often wondered if this issue could be due to something as basic as fluid brand, additive package, etc. I have done many drain & refills. I suppose I could replace with Nissan fluid but it would take years of D&R's to purge fluids completely. I may just try to ignore this annoyance and drive it.