P1619 code, trouble shifting 2000 V40
 

The CEL came on over the weekend on our 2000 V40 wagon. I had it read at the local parts house, but they couldn't read it for a Volvo for some reason. Checking online it came up as either a slow cooling fan or a transmission issue. I'm guessing the latter as the car is not shifting right. There is a flashing arrow indicator light on the dash and the car seems to be stuck in a lower gear. I can shift into neutral and back into drive and occasionally this will fix it for awhile. However, it returns and I'm wondering what to do next? The fluid level is good, and it was changed recently as well as the screen/filter being cleaned. At a loss on this one, advice anyone?