Checking the fluid first is a go idea here is the type of fluid and how to check it. If the fluid is okay, I would try an input shaft speed sensor. The location is in the images below.
Fluid Types
Automatic Transmission Fluid. Mopar ATF+4 or equivalent
Capacities
AUTOMATIC TRANSMISSION FLUID CAPACITY
SERVICE FILL
NAG1. 5.0Liters (10.6 pts.)
42RLE. 3.8Liters (4.0 Qt)
OVERHAUL FILL
NAG1. 7.7Liters (16.3 pts.)
42RLE. 8.3Liters (17.6 pts.)
NOTE: Overhaul Fill capacity depends on type and size of internal cooler, length and inside diameter of cooler lines, or use of an auxiliary cooler, these figures may vary.
Here is how they say to check the fluid though I can't see where to do it at, and you will need their special dipstick tool.
Clear the codes and then just turn the key on to see what comes up, these will be the hard codes, it seems like the PCM is out though. Check out the images (below). Please let us know what happens.
Images (Click to make bigger)
Monday, October 10th, 2022 AT 4:50 PM