2004 sebring convertible TCM issues
 

New to the forums looking for some advice. I have a 2004 Sebring Convertible 91k miles been rock solid until Oct 2023 when the check engine came on and transmission went into limp mode, local transmission place replaced the Powertrain Control Module and said that a bad ground caused it to short out, replaced the PCM and ran a new ground. All was good until recently when again I saw check engine, again car went into limp mode but this time saw error codes P1684, P0700, P0800 shortly after the engine light went out and car was fine again, same thing happened a week late, removing the negative battery cable cleared the error, week later it happened again and took it back to the transmission shop where they said the ground for the TCM was bad and cleaned the ground and reprogrammed the TCM it was fine for a week then happened again. Back to the transmission shop where they replaced the relay again good for a few weeks then the p0800 error code. At this point he thinks the problem is related to the fuse/relay box under the hood.

I notice that this only seems to happen when starting the car it hasn't happened while actively driving I also notice that the driver side headlamp is noticeably dimmer than the passenger side and oddly the drives side directional flashes rapidly (like the bulb is bad) but only when the headlights are on, like it's lacking sufficient power perhaps.

Lastly, I am seeing leaking transmission fluid. At one point it wouldn't go into gear so I added transmission fluid as it was low, that problem went away but I am now seeing a rough downshift at 25mph that only started when the fluid was low.

thank you

p0800 is not a valid code for a FWD car. p0700 means there are codes in the TCM that you will need a better scanner to get them. p1684 just the battery has been disconnected.

Thank you, apologies for the typo the code was 0880 which I believe is a TCM power issue.

As I mentioned in the original post the relay and the fuse were replaced. It only seems to happen when you start the car never while driving and so far as I can tell is pretty random I've experienced the situation where I started the car, drove 10-20 minutes stopped and when restarting 5 min later got the check enging an dthe p0880 code

Suggest having the battery and charging system tested A weak/failing battery or alternator can cause low voltage conditions and Chryslers do not tolerate low voltage conditions well. This can result in weird and seemingly random behaviors.

Be certain the battery cables are corrosion-free and secure at both ends. The dim headlamp points to grounding issues. It is tedious and time consuming but verify the ground points/straps in the engine compartment are all in-place, clean and secure. The adding of a ground wire also points to a ground issue that affects more than the PCM

Thank you the battery is new and I checked the cables but will check the charging system as well

ANy thoughts on the abrupt downshift at 25mph ?? This just started when I noticed low transmission fluid

Suggest dropping the transmission pan, replacing the filter and filling with licensed atf+4 only (no universal fluids - no additives). Fresh atf+4 has been known to resolve a number of issues with these transmissions. Fairly low cost first step in my opinion.

Note, when replacing the filter be certain the old o-ring is removed as it stays up in the valve body at times.

Thanks for all the helpful suggestions. I replaced the TCM and the relay and had a shop change the fluid and filter. The code went away for over a month and now has reappeared. I'm at a loss for ideas since I've changed the TPM relay in the engine compartment, the TCM and the fluid and filter. Is there a fuse or something in the circut I may have missed checking ?