Hey Mike:
I also have a 2001 Pathfinder with 81K miles. I also had some issues with the SES light a couple of months ago.
I reviewed posts on this websight and was resigned to paying $200-400 for repairs. I called my local dealer, made the appointment and took my vehicle in for service. When I went to pickup, same day --- the dealer's service department manager advised me there was 'no charge'. Evidently there is a Nissian issued recall for the SES light. Check with your dealer before spending any money or time to fix.