2009 TDI Q7 going into limp mode

My Audi Q7 TDI started going into limp mode. I have the same problem described here by another person on this forum
I have the VagCom and here are the engine fault codes. Can anyone tell what I'm looking at here?

008425 - Reductant
P20E9 - 000 - Pressure too High - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 165813 km
Time Indication: 0
Date: 2015.05.23
Time: 09:53:47
Freeze Frame:
RPM: 798 /min
Voltage: 14.14 V
Load: 49.0 %
Temperature: 11.7°C
6.5 bar
Temperature: 9.9°C
Voltage: 1.880 V


008430 - SCR NOx Catalyst Bank 1
P20EE - 001 - Efficiency too Low
Freeze Frame:
Fault Status: 01100001
Fault Priority: 2
Fault Frequency: 2
Reset counter: 255
Mileage: 166392 km
Time Indication: 0
Date: 2015.05.28
Time: 16:18:21
Freeze Frame:
RPM: 2100 /min
Speed: 106.4 km/h
Voltage: 14.36 V
Temperature: 324.0°C
(no units): 0.16
(no units): 0.39
(no units): 1.64


001027 - EGR Valve (N18)
P0403 - 004 - Malfunction - Intermittent
Freeze Frame:
Fault Status: 00100100
Fault Priority: 2
Fault Frequency: 4
Reset counter: 255
Mileage: 166379 km
Time Indication: 0
Date: 2015.05.28
Time: 15:08:00
Freeze Frame:
RPM: 966 /min
Speed: 6.7 km/h
Lambda: 0.0 %
Duty Cycle: 17.6 %
Lambda: 99.2 %
Mass Air / Rev.: 481.8 mg/str
Temperature: 25.2°C


001027 - EGR Valve (N18)
P0403 - 003 - Malfunction - Intermittent
Freeze Frame:
Fault Status: 00100011
Fault Priority: 2
Fault Frequency: 1
Reset counter: 255
Mileage: 166270 km
Time Indication: 0
Date: 2015.05.26
Time: 13:23:22
Freeze Frame:
RPM: 1701 /min
Speed: 38.1 km/h
Lambda: 0.0 %
Duty Cycle: 99.6 %
Lambda: 76.6 %
Mass Air / Rev.: 522.9 mg/str
Temperature: 37.8°C

For anyone else out there having similar problems here is what fixed my Audi to make the Engine codes go away.
NOx with labor installed $1200 (and adblue top up)
EGR value $480
EGR assembly $700
Labor for EGR job $500