Hi all, recently bought a Cabrio with elec fault, still not sure if it was a good idea or not, but hey-ho,
picked it up in Cocker mouth, drove to Keswick and ran VCDS, main fault jumping out was
Address 01: Engine Labels: 059-907-401-AKE.clb
Part No: 8E0 907 401 T
Component: 2.5l V6 TDI G000SG 0006
Coding: 07002
Shop #: WSC 00672
VCID: 3663C2FD12507F9184C-4B1A
Subsystem 1 - Part No: 00006059
Component: 130 106KC318_1.V14212800483
WAUZZZ8H6xxxxxxxx AUZ6Z0D0108897
2 Faults Found:
01126 - Engine Speed Signal
03-10 - No Signal - Intermittent
00550 - Start of Injection Regulation
08-10 - Control Limit Surpassed - Intermittent
Readiness: 1 1 X X X

engine was in limp mode But, no mil light on dash? strange, only revved to 2000 rpm but seemed to have a low amount of boost to get it there but really struggled up the hills.
stopped a bit later for a rest, got back on road and had full power, NICE!, booted it off a roundabout near home, and back to limp, no mil again.
anyway, checked the usual, connections for speed sensor, main ecu multiplug, but all is clean and clear, however, it is a yaki-taki speed sensor that's been fitted. Was about to order a new genuine speed sensor (G28) from Audi (£80 plus the dreaded!!), but before I did I thought I would check the timing of the fuel pump first just to be certain, did that, was in tolerance although the belt tensioner flags were slightly adrift, so lined them up and did a retard and re-align just to be sure.
So, I'm guessing, that it is just the speed sensor not being genuine that's causing the fault.

symptoms are generally, cold start, terrible, takes a while to fire up, but once running not too bad but is in limp mode, max 2000 rpm, once up to temp, shut down, restart, then have full power unless you boot it harshly, feed the power all is good.
after pump test earlier today, went to clear faults again, the start of injection regulation fault goes but, the faults for the speed sensors instantly return as below

Saturday,28,March,2015,18:26:51:05890
VCDS Version: Release 14.10.1 (x64)
Address 01: Engine Labels: 059-907-401-AKE.clb
Control Module Part Number: 8E0 907 401 T
Component and/or Version: 2.5l V6 TDI G000SG 0006
Software Coding: 07002
Work Shop Code: WSC 00672
Additional Info: WAUZZZ8H6xxxxxxxx AUZ6Z0D0108897
Additional Info: 00006059 130 106KC318_1.V14212800483
VCID: 3663C2FD12507F9184C-4B1A
Fault Codes have been Erased
2 Faults Found:
01126 - Engine Speed Signal
03-10 - No Signal - Intermittent
01126 - Engine Speed Signal
16-10 - Signal Outside Specifications - Intermittent
Readiness: 1 2 X 0 1

So, is it possibly just because its not a genuine sensor, although I've never had the rev counter drop out on me which I find strange as I assumed the speed sensor feeds the rev counter.

Any help from the collective would be, as ever, greatly appreciated.

cheers