bunch of codes after repair

I had my heater core replaced in my 2005 VW Jetta TDI. It has over 260,000 mi. When I drove the car to the mechanic the only issue was the smell of antifreeze in the cabin, no engine light or dash lights and the car accelerated like it should. While at the mechanic (when I got it back) I noticed two warning lights on and the glow plug light would not stop flashing, so I had the guy hook up the comp and these are the codes;

P0341/16725- camshaft position sensor, not plausible signal
P3102/19558- motor for intake manifold flap, no signal
P3338/19794- control circuit for glow plug ECU 1, electric malfunction
P1495/17903- switch-over valve for EGR cooler, open or short ground
P3373/19829- intake manifold changeover valve, open or short to ground
P0245/16629- solenoid valve (A) for boost pressure control, short to ground
P3101/19557- motor for intake manifold flap, open or short to ground

So, any ideas if all these are connected? I find it quite interesting they all happen at the same time and durring a heater core change.

I did also replace the glow plugs and their harness/wires three months ago, so all of that should be good. Like I said before, had no warning lights on before the mechanics shop. I would greatly appreciate any and all help before the bill climbs any higher.

codes

Did you have him clear the codes and then check if the codes reappeared?

I did, he said they immediately return. I've posted this on the TDI 101 as well with some more responces. I'm a newbie and wasnt sure where to put this post. Appreciate the help and I'd be up for any more suggestions you might have.