['97 Pathfinder A/T with an odd speedometer issue]

6 minutes ago, XPLORx4 said:

What you've described are strange symptoms. I do know that the VSS connects directly to the IC before it gets to the computer. Does your O/D OFF light flash when your start the engine? You could theoretically unplug your VSS from the passenger side of the transfer case and see if the symptoms change. If the problem persists, that would point to an issue with your IC. If the symptoms change or the speedometer doesn't move, it could be a problem with the VSS or the wiring from the VSS to the IC.

The O/D OFF is reading correctly, I live in a very hilly area and my commute requires a lot of transmission braking so I end up using it a lot more than most people would. 

 

As for the electrical stuff, I'll get back to you on that once I've tried what you suggested with unplugging the speed sensor, which'll be tomorrow as for some reason people in my house get mad at me when I start working on my car at 1:25 AM

['97 Pathfinder A/T with an odd speedometer issue]

Video demonstrating some of the problem, the noise that isn't the key turning is just the air coming on because I left the switch on. Sorry for the bad camera work but it's the best example I've been able to film.

 

https://www.youtube.com/watch?v=k6Sv_9V9uT8

 

Basically, when the key is turned to on - even if the engine isn't turning - the speedometer climbs to between 13 and 18 miles per hour. This offset is somewhat random, and this is just the top and bottom values for the range I've observed. When the car is off, it slowly falls back down to the resting position, however it does this at very inconsistent speeds and doesn't seem to always go to zero, instead sometimes resting at around 5 miles per hour and not settling any lower. It seems to fall much slower if the car has been running for a while. 

 

Under relatively normal acceleration and deceleration the speedometer will move at the correct rate up and down relative to my speed, and so it maintains this offset well enough to get an accurate reading of my speed as long as I remember it when I look. However, under rapid deceleration, the needle will move down significantly slower than the change in velocity, and will need a few seconds to catch up. Or catch down, I guess. 

 

This problem confuses me and I can't really find anyone who's had something similar or who has a guess as to what it might be. I haven't been super extensive in my efforts to fix it so far, though, which is one of the reasons I'm making this post; I really don't want to start pulling things apart and looking around without asking first, as it'd suck to pull the dash off and then realize it's an issue that didn't require that, for example. I'm inexperienced enough with auto work that my efforts to diagnose in repair are as much a liability (via making mistakes fixing or via failing to correctly reassemble things) as an asset, so I want to get as much info as I can before continuing. 

 

If anyone has relevant info on what this might be, what I should look at, and just any general info you'd think would be helpful, I'd appreciate it

 

Also, my first post here, or on an old style forum of any kind. Hi people! You all seem cool.