2007 Chrysler PT cruiser 4 door engine code B. 172,135 miles. I have codes P0700, P0882, P1684, P0218 now.

For a few months it will start in limp mode on occasion which is indicated by a hard shift after starting car. If I drive the vehicle during this key cycle the car will not shift out of first gear. If I restart the vehicle again it usually will have a smooth shift and drive fine. Once in a while the key has to be reinserted a couple of times before the car recognizes it is being turn to on and run positions. The number of restarts that it takes for a smooth shift out of park has increased drastically over the past couple of weeks of me searching forums for answers. I started messing with it this weekend first by checking battery voltage and cleaning the battery posts and cables which were a little corroded. I drove it the next day with minimal restarts occuring. I picked up a set of bolt on battery cable connectors and a cleaning kit. I installed the new connectors finding a cracked positive battery connector. I cleaned the battery posts. I drove the car down the street and parked it. When I went to restart the vehicle It had no power at all. I got the vehicle towed home. After more research and suggestions that maybe it was the TIPM I replaced it. Still no power. I cleaned all of the body ground connections. I got some spark when putting it together! I did the learn procedure for the TIPM. Started up and shifted out of park smooth as butter multiple times in the driveway. I drove to the gas station with a restart then to the store. Restarted with a hard shift. Restarted again and it was fine. The next morning I went to have battery and charging system tested. It passed all tests. I drove to the store came back out and it started with hard shift. I turned it off to restart and nothing no power. Went inside and bought a battery thinking that it has to have a bad cell or something. Came out installed it still no power. A guy helped me figure out I had a loose or dirty connection in my wiring. Got a tow back home. Replaced the negative running from battery to engine ground and to the body ground. The positive cable going to the starter which had signs of heat damage and corrosion. We have power! but the car is still starting in limp mode sometimes... any advice? Maybe related maybe not but on the last oil change the oil was thinner and it smelled a little like fuel. My initial thought was maybe because I was restarting the vehicle so much?

 

P0882 TCM power input low could be the PCM which TCM and PCM are one unit. Could be a TIPM issue where the power comes form to the TCM. Wire issue aka corrosion on a connector
Also need a better scanner to see the codes in the TCM to see what else might be there but that will get you in the right direction.