Chrysler Repair: 97 van: Intermittent No Power and speedometer fluctuates, odometer reading, dodge caravan

Question
I have a 97 Dodge Caravan that has a intermittent speedometer fluctuates and no power, had a scan tool on van the speed would drop on the scan tool as the dash. Took it to the dealer they replaced the PCM, when picked up the SES light was on with a code 1697 and all was fine for a few days. Drove it 30 miles and started to act up again. Any help would be appreciated.
Thanks

Answer
Hi Darrel,
I believe that the fluctuation of the speedometer in association with the power loss is telling us that the output speed sensor on your automatic transmission has worn out. That sensor not only runs the speedometer but its data is also fed to both the engine and the electronic transmission controller where it is factored into the operation of the powertrain itself.
You can change it yourself, and it costs around $100. You will find it on the side of the trans that faces the front of the van, just to the driver's side of the vertical gear shift control rod to which the gear cable is attached on its top. It is about midlevel on the body of the trans, and it has a similar looking sensor (the input speed sensor) on the passenger's side of the same vertical rod. You simply lift the tab gently on its plug and remove the plug. Then unscrew it and screw in the replacement (it is torqued to 20 ft-lbs, about the same as a spark plug). Reattach the plug and see if that resolves the problem. It is only because the speedo seems to flake out at the same time you loose power that I am led to this conclusion. If that is not the case, tell me more about the problem and what engine you have. A fresh code readout (free at an Autozone Parts store) would be worthwhile if I misunderstand the problem. The 1697 code probably had to do with the dealer not programming in something related to the odometer reading when the PCM was replaced, it shouldn't affect the way the engine runs.
Roland