300M with check engine light and P1684 and P 1776 codes
 

Check engine light comes on , no noticeable problems until coming to stop to turn or up to a stoplight. Transmission down shifts hard and sticks in low gear. ( all transmission position lights illuminate when transmission selector placed in "Auto Stick". transmission jumps hard when selecting "D" or any other drive selection. Diagnostic codes P 1684 , P 1776 and others show up on the OBD II reader. Cannot get it to do this when taking it to the dealership. Left car with Dealership and they could not duplicate conditions. Test drive with Technician.... No light or transmission problem. Just a few miles down the road from the dealership (After Service has departed) light comes on and transmission does it's thing again! Things "reset" when car is turned off for about 10 - 15 seconds and computer resets, all is well again. No light and transmission works normal.

Have gotten #2 cylinder misfire code as well as several transmission codes, but P 1684 shows up before all other codes in the chain of events.
Frustrated!

Swap out the relay labeled EATX or Transmission with a known good one. Drive it for a while and see how it goes.

Code P1684 simply means your battery has been disconnected within the last 50 starts. I know this because I too (yesterday) had the code. Possibly you can find a "new" tranny @ the junkyard.
Best of luck to you!

I like how people start threads and never come back. I might as well reply to this wall over here.

TNtech,
Just following YOUR suggestion. After doing as you suggested, the condition still occurs. no difference. still getting those two codes as well as others ..... however the other codes would logically follow if the transmission module resets while in operation. Codes such as misfire and valve in wrong position.

Just wish someone else has had this problem with this model. nothing in tech notes from Chrysler about this problem. May be a bad computer module, or bad computer.

Still frustrated!

Tranny working just fine as long as computer retains a good power connection. Tranny doing what it's programed to do when it looses power to the computer..... go into default mode! Just shutting the car off for several seconds and re-starting every thing works just fine. Sometimes the check engine light goes out .... sometimes it stays on. Sometimes the check engine light stays on and nothing happens with the tranny...... .

Still frustrated!

sounds like my problem with a 03 concorde , however i have yet to pull any trans codes. a new trans from junk yard was mentioned , i hope this is not the case , my ride only has 55k on it.

we prob have the same engine and trans? 3.5

P1776 - Solenoid Switch Valve Latched in LR Position (this is a transmission issue which may involve replacing the valve body and solenoid pack; on some models there is a TSB on this problem so be firm with your dealer / Chrysler).

Well if people start thread, they should atleast comeback and check what's going on..

9 times out of 10 the solenoid pack is the cause for the 1776