My wife's 99 Grand Prix GTP has code P0481. Car has never run hot. Replaced driver's side fan. Took relay out and checked it and it functions. With cover off of relay, and installed, squeezed the contact and the second fan runs. I read that the system uses the coolant temp sensor and the speed sensor but if one of these is bad wouldn't it cause a lot of other problems?

The car won't pass the emissions test until this is fixed. Any ideas?