shifts from 1-2 and then LOCKS UP in 2nd

[Siral3x]

Here is the story.
I got a "hybrid" 1995 Sonata with a 7 bolt turbo and a KM175-5 aka F4A22 tranny.
Never had any issue with the motor or tranny untill last night.
We had 8°F weather and I parked my car outside, next morning I go to start it, it barely starts put it in D and starts moving. IT shifts from 1-2 and then LOCKS UP in 2nd!
It will go in P, reverse, neutral and drive with no issues BUT in drive it shifts to 2nd then it won't upshift!
I tried everything with the minimal tools I had today and NO luck!
Here is what I've established so far:
-linkage is perfect;
-fluid level is perfect;
-took the TCU out and the board looks mint;
-checked all connectors on the tranny and couldn't fine no broken wires...etc ;
-decided to change the fluid, so I did;
-took it up the road and went up to 60MPH@5k rpm in a hope that it will budge loose and upshift;
-took out the external oil cooler and blew compressed air through it...I was thinking it was clogged BUT nope;
Nothing seems to work!!
Any input guys?? I mean I drove it 150 miles the night before and no weired signs or anything. It will go in reverse and work fine, N, and D. Even the shift point between 1-2 is RIGHT! Why is my tranny no shifting in 3-4(OD) after it has been sitting 1 nite???
PS:I had this setup for 40k+ miles now and it worked perfect!

 

[chanley talon]

I would check all fuses in your fuse box . Your tcu may not be getting power . You could check it for power.