Nissian Frontier

I have a 2001 Nissian Frontier S/C with 147000 and the abs light comes on and goes off but when it goes off a noise is made toward the front of the truck is this serious?

Could be.

A wild guess is that the wheel sensor is erroneously telling the ABS system that the wheel has stopped rolling, the ABS is modulating the hydraulic pressure to that brake, and when the signal continues to tell the ABS system that the wheel is still sliding the system is thinking that it is not stopping the wheel from sliding and it’s tripping a fault code, energizing the light.

That’s just a wild guess, you understand. Why not get it checked out?