transmission stuck in limp

Hi Guys, I was hoping you could help me with a problem on my grandfathers 2000 v70. The trans is stuck in limp mode. The up arrow is flashing and the check engine light is on. these are the only lights on. the codes i pulled are P0702 and P1618. It seems to be an electrical problem but I'm not sure where to go from here. Any help would be appreciated Thanks.