Hyundai Repair: 2006 sonata, 3.3 6 cyl, transmission control module, sonata 3

Question
Jan. 2nd the temp. was -30 degrees. We drove about 100 miles and stopped for breakfast. When we started the car the check engine light came on and it would not shift into high gear. We drove about 8 miles home and checked the codes, it was P0890.
  It does drive OK now and the light is off.

Answer
P0890 indicates insufficient voltage was received on the ATM control relay circuit.  If the voltage on this circuit is low, the transmission control module (TCM) will be unable to activate the transmission solenoids, causing it to put the transmission in failsafe (3rd gear only).

Most likely, there is an intermittent problem in the relay itself.  I'd recommend replacing the ATM control relay in the underhood fuse/relay box and seeing if the problem returns.