Chrysler Repair: 91 mini-van electronic trans drives in 2nd gear only, plymouth grand voyager, speed sensors

Question
i have a 91 plymouth grand voyager and i am haveing a problem with the transmission before it was going into 2nd quite often and staying also if i was going 40 or above it would go in neutral until it went below 40 then into 2nd now it will be driveing fine and all of a sudden it will go in to what seems to be neutral no gears work i can turn it off and back on it will work for a few seconds and right back to the same thing. i have changed the speed sensors and i know its not the transmission because its not slipping and has pull any ideas

Answer
Hi Brian,
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Hi Brian,
It sounds like you have the A-604 4-speed electronic transaxle. About the only way to find out what is wrong with it is to do a code readout of the transaxle controller via a blue 6-pin plug that is mounted under the dash to the left side instrument panel support and using a Chrysler Diaganostic Readout Box II or equivalent code reader of the OBD-I generation code system. There is a 2-digit number coded in the memory of the controller that will give us some ideas as to what is wrong. When the trans defaults to 2nd gear it is called 'limp-in mode' and its purpose is to put it in a gear where the least amount of potiential damage will occur until the problem can be solved. You can get this readout at an independent transmission shop or a dealer if they have the readout box to do the job. Get the number of the code, what it means, what they say needs to be done, and at what cost. Then follow-up telling me what you have learned.
Roland