Sure would appreciate some input on a check engine code 12. Was given this car from my mom & from what I see it has several problems that need to approach.

 

Welcome to DF
Code 12 is battery disconnect and 55 is end of test.

 

Code 12 actually means keep alive memory power feed wire connection was disrupted to the PCM. If the battery has never been disconnected in 255 key cycles or never went dead, then there could be an issue with that electrical circuit.