1999 Suburban P1810 diagnostic code

I pulled this code tonite from my suburban. Light just went on last night. All I can find is that it indicates an Auto Transmission Fluid Pressure Manual Valve Position Switch Malfunct B

Ok, I have NO idea what that means. Can anyone shed some light on the subject?

The automatic transmisson fluid pressure (TPF) manual valve position switch consists of five normally - open pressure switches. The vehicle control module (VCM) supplies battery voltage to each range signal.
If the VCM detects an invalid state of the TFP manual valve position switch circuit by deciphering the TFP manual valve position inputs, then DTC P1810 sets. DTC P1810 is a type D DTC. For California emissions vehicles DTC P1810 is Type B DTC.
Troubleshoot:
1. Inspect for proper adjustment of the transmission linkage from the select lever to the manual valve. Each pressure swicht controls a transmission drive letter: hence R, D, OD, 1, 2. Adjustment is critical.
2. Inspect the fluid: levels and condition of it.

Look according to my volume 3, shop manual on page 7-397 there are 9 action steps to be taken to solve the problem.
If you are going to do the work yourself, you need to get this information to proceed accordingly.
ralonso