Okay so last night my check engine light popped up. I figured i'd try to reset it by turning the car off and back on. No go. So I drove on it to see if it would correct itself, still nothing. So this morning I woke up and went to go retrieve the P code and its a P1698 No CCD/J1850 Message From TCM/PCM. I don't know if it is from the TCM swap I did over the summer because I haven't had any problems with it for 3 months. The D runs fine still so I don't know where to start. Any help is appreciated. Thanks in advance!

 

Your TCM is not communicating with the PCM. Could be a shorted wire, could be a bad TCM...

 

Well just last night the light went away, but even if it was a bad TCM why would it be doig this now after three months? It shifts just fine still too.

 

I would check and clean all of your connections at the tcm and pcm just to make sure.