Check engine light on 97 Concorde

The check engine light came on this past weekend for my 97 Concorde LXi
with 3.5L V6.

I just had the oxygen sensor replaced last month when the check engine
light came on.

The light dildn't not come on last evening or this morning when I took
the car in to check this out. The service department said it would not
be worthwile to check out since the light was not currently on. I really
didn't want to spend the money since I was just laid off two days ago.

There is a problem though that occurred at the same time the check
engine light came on. The automatic climate control is not working
properly (blowing cold air when the interior of the car is cold etc.)
The trouble codes pulled by a friend who used to work for a mechanic
were "12" and "43". The dealer said these were "generic codes" and of no
help.

Any input would be of help. I really am not in a position to spend money
for repairs but I WOULD like to have heat in the car.

Thanks for any input.

 

Code 43 typically refers to 3 different problems:

- Peak primary coil current not achieved with max dwell time
- Cylinder misfire
- Problem in power module to logic module interface

Most likely lower intake manifold gasket leaking around cylinder 5,
causing mis-fire, IIRC. Seems to be a common problem on the 1st
generation 3.5L.