I have a 2004 mountaineer that iv had had a lot of problems with. I got a msg. on dashboard, engin fail safe mode.it died while i was driveing.Restarted and maid it home.The belt had started sliping that day.I replaced belt,removed neg. battery term.engin started, drove 1/4mile It died again .Engine failsafe mode.Naw engin rotates will not start.No error codes detected by scan.PCM has been replaced,along with transmission rebuild, and other repairs.Iv worked on cars ,motorcycles my hole life and a pro A/C tech. so i have some expereance.

 

failsafe is a limp home mode to keep the engine from blowing up in the boonies. normally the mode is because the engine is overheating,you will lose power as some pistons are used to cool off the block.breaking and steering will be hard to do.
The owners manual does talk of the failsafe mode.