My name is XXXXX XXXXX I'd like to try to help you with this problem.
Roadspeed information is gathered using the transmission output speed sensor. This information is processed by the transmission control module and then shared with the other components that need this information.
Ok, if the check engine light is on, it would be a good idea to read the powertrain codes. The transmission codes won't be available on a basic code reader... you'd need something that supports enhanced Chrysler diagnostics.
Do you intend to test this yourself? You'll need a digital volt/ohm meter to do the basic checks.
I'll put together some images and test points for you if you like.
Try cycling the key on, off, on, off, on and see if you get anything on the odometer...
This will only read the codes from the PCM , not the TCM.
Here's what the output speed sensor looks like. It's on the transmission.
I'd suggest you leave it alone for the moment. Sometimes disturbing a connection makes a problem temporarily go away. I'm going to suggest that we disconnect the TCM and measure the resistance of the circuit.
TURN THE KEY OFF AND DISCONNECT THE CONNECTOR ON THE TCM.
This is what the plug looks like.
Here's a partial list with an index of terminal numbers. I've circled the ones for the OUTPUT SPEED SENSOR (OSS for short from this point on, ok?)
I want you to measure the resistance between pins 13 and 14.
Is it showing an open circuit? What is the resistance?