I have a 2000 audi a4 Quattro, auto/trip transmission. Today on my way to work, my car would jerk every so often on the highway right around 3000 Rpms... I got it home and it died at the end of the street. My
Vag-com throws
17925 (p1517) (main relay fault)
17972 (p1564)(throttle body control voltage to low)
17953 (p1545) (throttle body control malfunction)

I'm trying to figure out what's going on. My relay was tripped when after replacing the alternator, but I pulled it out and stuck it back in and my car worked great after.
I'm trying to figure out if this is just a bad relay or if it's a bad throttle body.

Help! Please.

Thanks