Greetings Community, I own a 1997 Jeep Cherokee Country and recently had my check engine light come on and need help identifying the codes. The first string of codes was: 12, 13, 43, and the second was 43, 43, 42, 55. Inspection and registration is coming up and I need to try to fix this problem ASAP. Any help would be greatly appreciated.

 

If you have a '97 (assuming you still have the original drivetrain and electronics), you need to get an OBD-2 code scanner, plug it in and write down the codes. The codes you just rattled off here are all OBD-1 or pre '96 era codes.
If your jeep is older than '96 -
12 and 55 are irrelevant
13 is a MAP sensor issue (not necessarily a faulty sensor)
43 is a misfire (OBD-1 won't tell you which cyl though)
42 has several possible triggers, but I would fix the cause of the misfire first.

 

12 battery to over was disconnected
43 p0300 multiple cylinder miss fire
13no change in map from start to run
55 belive sequence ended