CEL codes and fixes?

I did the turn key thing with my 97 4.0 and got these codes: 12 43 42 55 (In that order). I had them for quite a long time, and the same ones return after resetting the computer. I did a stroker, and they didnt show up at first but now the exact same codes are back. I looked them up in my haynes manual and found out:
12- Alternator light stays on. I dont know how exactly to fix this, I dont have any charging problems.
42 - Noisy in one particular gear. Havent noticed anything, even changed transmissions for different reason and still got the code.
43 - Slips out of gear. No, hasnt happened. Again I had the same code before I replaced the old trans, and after the new one was in. New throwout, pilot bearing, clutch, no "slipping out of gear."
55- Vibration. A lot of stuff has been changed in regards to what haynes says. Trans, rear axle, engine, rear driveshaft. Nothing in pursuit to fix this code, just stuff along the way.

I cant seem to get these particular codes to go away. Every once and a while Ill get a 21, that it is dieseling. It isnt, and never has. Is it just my computer being retarded, or are these actually problems Ive yet to fix even when replacing parts?

i thought the key thing only worked up to the 95 model year you need obdII to read 96 and up codes thats prolly why nothing makes sense

kennzz05 said:

i thought the key thing only worked up to the 95 model year you need obdII to read 96 and up codes thats prolly why nothing makes sense

Click to expand...

Nope, I can get them on my 96. Got them on my 97(rip) also.

I know 12 is: Battery disconnected in the last xxx starts. Or something to that effect. Basically just the start of the codes.

55 is: End of codes.

You need to get a FSM for a 97 or go have it checked on a code reader. Some of the #'s changed year to year. JIM.

I would get somebody with a scan tool or a reader capable of "clearing" the codes to do that for you. Then start fresh and see what codes return and stick. Gottta have the right hardware to clear the codes. Don't want to be chasing ghosts.....BTW, let us know what key on sequencing you used to pull the codes on your 97. I tried it on my 99 and it didn't work; I was under the assumption that it didn't work on OBD2 systems either???

I guess the cutoff was somewhere in 97. Turn the key on but dont start it then off three times really fast. Then leave it on on the fourth I think. I have the FSM but I knew where the codes were in the haynes manual off the top of my head. Ill check with the FSM later today.

Edit: Just found out 5-90s site has codes that make a little more sense.

12: Direct Battery Input to PCM disconnected in the last 50 ON/OFF cycles. I guess the only way to fix this is to drive it enough times, I replaced the battery sometime in September, but I have a funny feeling it has been through 50 cycles.

43: Cylinder misfires. My Jeep has had a condition for years where if you drive it then park it and drive it again within a certain time period, it will stumble for a couple seconds. If you let off the gas it wont come back again until the same conditions are met. It is usually around a speed where I can shift so it has never caused me any grief. Could this be related?

42: Either ASD issues or fuel pump or fuel level sending unit. Dont know what Auto shut-down is, but my gas guage gets whacky sometimes. Makes sense.

55: Display of codes is finished. Again, makes sense.