D3 4.2TDI DPF Pressure Sensor

[paulrstaylor]

Apologies for my first post being a request for help but I have been a lurker for a while and an A8 parts customer

I have a 2005 A8 4.2 TDI, circa 125K miles on the clock and it has just started showing an amber engine warning light, I have checked with VCDS and the following error is showing. Clear the code, the light goes out for a day or so and then returns.

Address 11: Engine II Labels: Redir Fail!
Control Module Part Number: 4E1 910 409 A HW: 4E1 907 409
Component and/or Version: 4.2L V8TDI G000AGSª0070
Software Coding: 0011773
Work Shop Code: WSC 00503 503 81333
VCID: 22400330FDD4D09
1 Faults Found:

012298 - Diesel Particle Filter; Differential Pressure Sensor; Bank 2
P300A - 003 - Implausible Signal
Freeze Frame:
Fault Status: 01110011
Fault Priority: 0
Fault Frequency: 1
Mileage: 200079 km
Time Indication: 0
Date: 2012.06.13
Time: 20:08:43

Freeze Frame:
RPM: 0 /min
Pressure: 0 mbar
Pressure: -21 mbar
Temperature: 87.0°C
Temperature: 87.0°C
(no units): 0.0
Pressure: 0 mbar

Google suggests that I need to replace G450 or possibly G451 sensor? Has anyone come across this before or can you give me any tips? Is the part something that is best from a dealer or elsewhere and where will I find the sensor on an 8?

Thanks in advance

Paul