Dodge Repair: 01 Caravan code P1788, shifting into overdrive, test failure

Question
This code is coming up constantly even after clearing it.   Symptoms are not shifting into overdrive.      What am I looking at changing here and can I do it myself ?

Answer
Symptom:
P1788-2/4 HYDRAULIC PRESSURE TEST FAILURE
When Monitored and Set Condition:
P1788-2/4 HYDRAULIC PRESSURE TEST FAILURE
When Monitored: In any forward gear with engine speed above 1000 RPM shortly after
a shift and every minute thereafter.
Set Condition: After a shift into a forward gear, with engine speed > 1000 RPM, the TCM
momentarily turns on element pressure to the clutch ckts that don’t have pressure to
identify the correct pressure sw closes. If the pressure sw does not close 2 times the code
sets.
POSSIBLE CAUSES
LOSS OF PRIME P1791 PRESENT
RELATED DTC’S PRESENT
TRANSMISSION FLUID LEVEL
INTERMITTENT WIRING AND CONNECTORS
TRANSMISSION CONTROL RELAY OUTPUT CIRCUIT OPEN
2/4 PRESSURE SWITCH SENSE CIRCUIT OPEN
2/4 PRESSURE SWITCH SENSE CIRCUIT SHORT TO GROUND
2/4 PRESSURE SWITCH SENSE CIRCUIT SHORT TO VOLTAGE
INTERNAL TRANSMISSION
TCM - 2/4 HYDRAULIC PRESSURE