Your 871 code does not show up as a valid code number.
However there is a tsb for the 1776 code that should be followed.
MIL Illumination - DTC P1776 Solenoid Switch Valve Latched in LR Position
If the vehicle operator describes a MIL illumination and the technician finds DTC P1776
Solenoid Switch Valve Latched in LR Position is set the DRBIII® can be used to access
the event data screen and look at the "TRS Code" reading.
NOTE: The solenoid switch valve is not in the solenoid pack it is in the valve body.
TRS Code Reads TR2
If the "TRS Code" displays "TR2" it is an indication that the manual valve was not fully in
the OD position at the time the DTC was set. Check the shifter cable adjustment and
adjust if necessary. Also check the shift control system for excessive friction and/or routing
TRS Code Reads OD
If the "TRS Code" displays "OD" then a sticky solenoid switch valve is the primary cause.
Perform the proper diagnosis for the valve body. Inspect for foreign material in the solenoid
switch valve and plugs.
**FOR 2002 - 2004 LH MODEL ONLY**
**If replacing the valve body assembly for DTC P1776 Solenoid Switch Valve Latched in
LR Position first inspect the build date on the solenoid pack (Fig. 1) or (Fig. 2). If the build
date range falls in between 3001 and 0603 replace the solenoid pack not the valve body**.
Because this requires the use of a scan tool to gain the TRS failure code, you are best to let a shop diagnose this for you otherwise you will just be guessing between the two.
2. No, the solenoid pack is external.
3. LH is just the body code for the Intrepid, Concorde 300M.