I've got a 1998 Altima thats been having a hard shifting problem for
some time now. I got the trouble code from the ECM and it was
1205(P0745), Line Pressure Solenoid Valve. So i ordered an new solenoid
pack and installed it with out any issues but the error was still there
and so was the hard shifting. So back to the net for some more
searching. I found a lot of people talking about the dropping resistor
so i decided to look in to that. I've checked it out and appears to be
fine because I'm getting a proper ohm reading on it. I've read alot
about the Transmission Control Unit having an issue but not sure how to
check it out with out just getting a new one. I dont want to spend any
more money on this damn problem until i know what it is.

Also, when I turn the ignition switch on the O/D light comes on for a
few seconds and then flashes 16 times. I think its because there is an
error but i dont know how to read the codes from it. I found some
instructions for how to but it didne mention for what years and it
doesnt work for me.

So any help on the TCU trouble codes and just fixing the problem would
be greatly helpful.