Thanks Transdude, I'll check it out. Just thinking about it, I havn't checked the fluid level for a long time, since it never has leaked any in its 187,000 miles. I changed the fluid and filter at 150,000, and don't think I've checked the level since! Stupid of me, years ago that was the first thing I'd look at with tranny problems.
Thanks for the tip on the MLPS test - I'll watch carefully for that in the future. I did have the AC, defrost, etc off and it was in park during the error code tests - before I replaced the MLPS, I could clear the codes and rerun the test and the code would be gone. A day or two later, it would give the code again, so I think it stored it sometime while driving, but it doesn't now since I replaced the switch.