Mopar,
This problem has been discussed before on TBN. From another post:
<font color="green"> Short, long, long, short or .--. is indeed the fault code for the mfwd sensor . If you have cruise control it will not function. The flywheel speed sensor is also the same part # as the mfwd sensor. So in my opinion the flywheel speed sensor could possibly fail, Their is an internal wiring problem inside certain speed sensors. Deere has corrected the problem with a fix as fail . This doesnt mean that everybody with e-hydros has to worry, not everybody will experience this. contact your dealer. The kit consist of both the mfwd and flywheel sensors and take about 5 minutes to install.
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And another:
<font color="red">Note that the MFWD sensor error can also appear without their being a problem present. If you depress a pedal with the gear lever in neutral, then this error will appear after about 5 seconds. It could also apper if under a heavy load the hydrostatic transmission goes over relief and you hold it that way for about 5 seconds. Basically, if the microcontroller doesn't see a certain gear move while a foot pedal is depressed, then it will flag this error after about 5 seconds of this condition.
If your cruise control works, then you don't have to worry about your sensor. </font>
Hope this helps.
Jeff