Check engine codes associated with cold?

About the same time as the cold weather hit my check engine light came on. I've got a 96 Sport, 4.0, AW4. I replaced the battery about two weeks before the light came on. I got codes:

12 - Memory cleared between 50-100 starts. (Not worried about that one)
17 - Low engine temperature. (Is anyone else getting this?)
21 - Oxygen sensor signal - neither rich nor lean condition detected from oxygen sensor input. (due to low engine temp?)
42 - Fuel pump or no autoshut-down (ASD) relay voltage sense at controller.

Is anyone else getting codes due to the cold? The vehicle seems to run fine. It starts with no trouble, idles normally and accelerates as usual.

Thanks,

Fix the problems and the codes will go away. Cold or not, your Jeep is telling you it has a problem.

1996 is OBD-II isn't it ? Download, and write down, and post the four digit OBD-II trouble codes, they are more specific as to the exact nature of the problem.

Will do.

Thank you,

I'd recommend starting with code 17. Temp too low.

What is the coolant temperature reading on the dash gauge? The target is 200-210.

If you are not there, you need to find out why. You could have a bad thermostat, or it is possible that the coolant temperature sending unit that is providing this input signal is bad.

This problem is NOT related to the cold outside temperatures. You have a hardware problem within your Jeep.