Chrysler Repair: 1994 T & C van: transmission lock-up/no speedo, automatic transaxle, turbine speed

Question
Roland, Thanks for your help. One problem I have with the van is this will be the 5th (number 5) transmission rebuilt since I have owned it. I thought maybe it was just a simple sensor, I did take it to a shop to have the codes read, but when they hooked up the test equipment the display went blank and so did my instrutment panel. Could not get a reading of the codes because eveything went blank , like the test equiptment and the computer were not communicating
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Followup To

Question -
I have 1994 town and country van, the speedometer reads 0 and the transmission will not shift. I have replaced the output speed sensor and the turbine speed sensor as well. no help. Can not find any information as to what sends the singal to the speedometer. Can you help?

Answer -
Hi Jeff,
Because you have the electronic automatic transaxle I believe that the speedo and the transmission control are based upon the output speed sensor of the transaxle and its signal to the speedo and to the powertrain controller is generated in the trans controller and carried on the CCD bus as digital data. So it could well be that you are having a CCD bus data handling problem. The best way to find out would be to find a dealer or trans shop that has and OBD-I generation reader called a Chrysler DRB II along with a body data link connector that matches to the under dash 6-pin blue plug so that the status of the CCD bus can be ascertained and also a readout of the fault codes from the transmission controller. The trans appears to have gone into limp-in mode which is a self-protective status that protects other parts of the trans when it detects a malfunction that might do damage elsewhere in the trans.  A fault cods(s) will be placed in the trans memory. If you get some readings about the data bus and/or the trans memory codes and would like some interprestation, write me back with the specific code results of those tests. I can check several manuals I have for the 94 trans and data bus to see if I can help you get to the bottom of this problem. You may ask at the shop if the readout will be credited to the bill if you authorize a repair to be made. So get this diagnostic information before getting into a rebuild of the trans or other very expensive repair. Take your time so that you know for sure that the proposed repair will repair the problems. Otherwise money can be wasted and frustration incurred.
Roland

Answer
Hi Jeff,
Was the test done thru the data link connector under the dash? Did they use a Chrysler DRB II unit?
According to the data bus manual I have, the corrective action for blank screen is to verify whether you are getting 12v on the red wire at the plug (middle pin of three on the side of the plug with the notch at the corner) and to test the black/light green wire pin on the other side of the plug directly opposite the notch to see if it is grounded. If it passes those tests, then try a different cable, a different cartridge, or a different DRB in that order. So see what you get on the first two measurements and maybe we can go from there to get you a readout.
Roland