Chrysler Repair: Transmission problem: limp-mode in hot weather, weather question, trans repair


Question
QUESTION: I replaced the transmission on my 2001 Sebring 4cyl. LX in Sept. 2012.
Car ran fine all winter until, on the first hot day this spring, the car put itself into limp mode in New York City. I went to a local mechanic and got an 0700 code. He reset the computer and car ran fine to get it back to original trans. repair shop who checked it out and couldn't find anything. Drove auto to Fl. where upon arrival and shut off (on a very hot day) the vehicle went into limp mode upon restart (2hrs.) Replaced input, output, and trans control mod. Auto test drove OK but on restart (after sitting in hot sun) car went back into limp mode. I removed battery ground, reset computer, and drove back in cooler weather to New England with no visible problems. Now after sitting in traffic in NYC car slipped back into limp mode. I, once again, removed the battery cable, reset the system and auto shifts now. It seems,  after all this, heat is the dominant factor. Please help. Any advice, including trading car in, would be appreciated. Thanks,

ANSWER: Hi Paul,
I assume that you checked the fluid level in the transmission. Use ATF + 4 if needed but don't overfill. I would suggest that you put a light behind the radiator and see from the front if the fins of either the radiator or transmission fluid cooler coils is clogged up with dirt so that air is not efficiently cooling off the trans fluid. If it is, hose that dirt away,
I would then get a fault code readout using the plug-in code reader which an independent shop will do for $40 but do it after the next experience with no shift and BEFORE disconnecting the battery. The 700 code means there is a second or more codes also in the memory but you should get it done with a plug-in code reader. Let me know what other codes you get and that will tell us what is wrong in detail
Please 'rate/nominate' my answer/me (see the PS below).
Thanks,
Roland

---------- FOLLOW-UP ----------

QUESTION: Roland,
I took your suggestions and did just as you said. I drove the car for about 2 weeks and eventually it went into limp mode. I used a hand scanner,  and got a "no code" on it. I then took the car back to my mechanic, let him use it for a week. He reset the computer and eventually it went back into limp mode. He put his scanner on it and got the same results. No codes came up. For a while the car ran fine.  Recently, the car went back into limp mode and a turn of the key revealed a P 1684. After I got the code, via the odometer, the car then acted and shifted normally. Even though now it seems to shift OK, I still get the 1684 code when I turn the car off and I prompt it with the ignition key.
Thanks,

Answer
Hi Paul,
The 1684 code says that the connection of the battery to the powertrain control module has been interrupted some time in the past 50 starts. Be aware that when you disconnect the battery to erase past codes that will provoke a 1684 to be set, nonetheless.  Absent a recent Fewer than 50 starts) purposeful battery disconnection the 1684 suggests that there is a loose/corroded connection of either of the battery cable clamps/wires connected to the clamps, or a similar issue at the ground point of the (-) post battery cable to the chassis (on the left strut tower) and at the engine on the rear surface (below the oil filler cap). So check all those battery connections would be my suggestion at this point. It might also be a loose connection of a (+) battery post wire to the powertrain controller and I can tell you about those after you check out the (-) post connections. A momentary battery disconnection could very well throw the trans into limp mode. With no other transmission specific codes however I can't suggest anything directly related to it as the limp mode cause.
Please 'rate/nominate' this answer/me (See the PS below).
Thanks,
Roland