Emission System light is on please help

[cruzzen]

Was driving and the emission system light kept on flashing on and off them after a bit it stayed on for good.
Got home and it is leaking water.
We are not sure what it could be as temp is down and everything else seems to be fine apart from when we are driving it does this pulling and you can feel it when driving.
Has this happened to you or you have heard of this before?
Please help

 

[BigRondo]

Did you get the codes read? If not, get the codes read and post them here and we can dive in and try to help you!