U1027 Invalid or missing data for engine rpm
 

I have had this code forever. I changed both the vss and oss speed sensors and I am still pulling this code. I'm on my fourth Transmision and don't want to put a fifth one in soon. If anyone has any ideas to help my weak freestar Transmision that would be great.

Hey, Did you ever get it solved? I have a code U1059 that the ABS circuit is not communicating with the instrument cluster. Any ideas what specific problem that could be?

More codes now
 

I have more codes now. I also have U1059 and U1041 vehicle speed signal missing or incorrect. Any help would be great. Definitely never buying a Freestar/windstar again.

Not knowing what equipment you might have to work with, a good place to start would be to check for a possible blown fuse. Then you might confirm you have vehicle power ,12 volts at pin 16 of the DLC, Data Link Connector ( under the dash to the right of the steering column).

Because different models use different network set-ups it is important to know the year and model of the vehicle.
Sometimes a few simple checks can isolate a communication problem with a network, if the simple checks don't reveal the problem , more detailed checks are required which can require the use of a quality scan tool.
I can understand your frustration with your particular vehicle, but just about all vehicles these days have many modules and different types of networks and troubleshooting them can consume a lot of time and require a schematic diagram to even determine what type system is on the vehicle.
It is necessary to know where the info comes from and goes to in order to determine where a piece of information gets lost . That is where the wiring diagram comes in. In the case of the problem today involving "U" codes , they are generally indicative of a communication problem within the network and that can include shorts, opens or interrupted signals due to wiring problems and not necessarily sensor problems. Even a faulty module can not respond to the info sent to it.

Grounds, grounds, grounds. There is a network of grounds on the Freestar. I would start with making sure that they are clean and making good contact and they are the master communicator.

You will find a group of grounds on the left and right side under the black plastic radiator cover. There is one on the A/C Dryer/Accumulator. There is one on the drivers side behind the plastic kick panel. Any of these grounds not having good contact will cause all kinds of gremlins to appear. Also check the tranny ground, battery connection and any other ground you can fine. A good cleaning and some dielectrical grease goes a long way.