You need a crow foot spanner!!
+1^^^^
The VCDS fault code as previously directed points to no gas.
I'm puzzled at the pressure sensor being an issue to change (I've done a couple and found them no trouble on 07 cars) but that has to be your starting point if your going to have the system regased.
You must do both the pressure sensor and the seal (the sensor is the common problem as the gas seeps though the plastic housing) as below States it changed part numbers a few times so they know it's a problem!
Now the sensor(G65 is it's technical description) was originally 1K0 959 126 A
Today that is 1K0 959 126 E - £61:36 full retail inc vat
Seal 8E0 260 749 - £0.77 part number remained the same thus no improvements needed!
Online parts catalogue details
http://www.partscats.info/volkswagen/en/?i=cat_vag_models&brand=vw&number=1714&set=1728&ein=2007&f=474&hauptgr=1234567890&hg=2&grf=026041409&bf=26041&hgug=260&ug=60&parent_id=2341754&detail_id=2341814Now when the system is recharged "request they fill it with the dye mix" cause some people don't so they can charge you again!
This allows fault finding using a UV. Light after a period of usage (typically 14 days).
Now major leaks are normally quite obvious and show at the time of recharging if a stone has holed a condenser etc.
However, sometimes you can get leakage so small without the dye you would never detect the fault!
A recharge in Newcastle can be undertaken for £35:00 including the dye.
Now the system can suffer from many problems but this re-gassing should really be undertaken every 24 months (as both system oil and gas loss is expected) so for it to be an efficient system they recommend this!