Could be the clutch pedal switch? I had this problem last year and it did not show up on the VCDS diagnostic. You will probably only find out if its this by replacing it, but it is a fairly cheap part to try first.

Unfortunately my local VW Van centre decided that they would try everything else, including taking the steering column apart, first and charge me for it, so I ended up pay £120 for a £15 fix hsy: Lesson learned

 

VCDS show clutch pedal switch OK if there is only one switch.

Fault codes
1 Fault Found:

18097 - Powertrain Data Bus
P1689 - 000 - Implausible Message from Elect. Load Controller
Freeze Frame:
RPM: 0 /min
Torque: 173.2 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 12.16 V
Bin. Bits: 00001100
Bin. Bits: 00000000
(no units): 1.0

 

OK, check out the thread here http://www.briskoda.net/forums/topic/70937-cruise-control-problems/ as it has the same error and seems to indicate a fault with the cruise control wiring.

 

One wire was broken.

 

Hi. I have the same problem, which wire and where was it broken