2001 Jetta GLS smells like a sewer

I have a 2001 Jetta GLS that is stinking up the roads. Engine light is on. When the car is on, a smell comes from the engine that is brutal! If you drive behind the car it can gag you, not to mention if you roll down the window while you are in the car...

Anyone know what the problem could be? Please help!!!

Have the codes read. Whatever the problem is it probably has destroyed the catalytic converter.