I have a 96 Nissan Sentra GXE.  Recently my check engine light lit up
and stayed on.  I came on when the car was overheating because of a
faulty radiator cap which I replaced.   I am trying to figure out how
to pull the codes to see if there is anything else wrong.   I know I
can get an OBDII reader, but I also thought you can pull them by
making the ECU flash out the code.   How do you do this?

Thanks,  Al Kondo