Chrysler Repair: Output speed sensor code/Odorless vapor:A/C, chrysler town and country, weather seal

Question
We have a 1999 Chrysler Town and Country.  Cany you tell me what a it means when you have an OBDII code of transmission control system malfunction.  It came up with the ouput speed sensor code.

Also we have clear vapors coming out of the vents.  It was odorless.  Also when you turn off the A/C, it makes a release of pressure noise like a shhhhhhhh sound for a while after you turn it off.  Could this have something to do with the heater core?  Also sometimes the air isn't getting that cold then that pressure noise comes on and then it starts to get colder.

Thanks for your help

Answer
Hi William,
The output speed sensor code typically means that the sensor has failed and needs to be replaced, though a problem with the electrical wiring to the plug at the sensor might also be the cause so you would want to visually inspect that before buying the sensor. The output speed sensor is located at the very end of the powertrain, on the side that faces the front of the van, just to the left (toward driver's side of the vehicle) of the veritcal shift control rod, about midline height. It has an electrical plug which you should remove being careful to take off the weather seal for reuse with the new sensor. Then using a box-end wrench unscrew the old sensor and replace it with a new sensor. If you buy a new sensor it will help you to identify the old one for removal.
On the AC vapor, if it is odorless it may just be a problem with the condensation of moisture on the coils that is not draining from the hose outlet on the drainpan inside the cabin into which it drips. (Heater core Coolant or A/C Refrigerant usually either has an odor or a film that coats the windows if that is leaking). If you look under the van after you have driven for a while with the A/C in use you should find some water dripping on the ground below the firewall near the midline of the van. If not, then the hose outlet is probably clogged and needs to be cleaned out. Use a stiff wire inserted in the nipple of the hose from under the van to clean out the passageway. Other than that, it would be adviseable to go to an A/C shop and let them observe what you are describing.
I hope that you can solve both of these issues yourself.
Roland