Passat OBD code P1296 Help!

Hey guys,

I am actually posting this for someone else.
She has a 2001 Passat and I had her go out and get an OBD scanner after the dealer claimed to fix the problem and reset the CEL only to have it come back shortly there after. I would love to help her get this fixed so do you have any suggestions as to what this could be and what is causing this code?

When I look up the code I see it is:
17704 P1296 Cooling system malfunction

Here is what was suggested:
P1296 - Hmmm, VESIS list this as a coolant system issue, to which I've replaced many Coolant Temp Sensors that have caused DTCs. Based on the track record VW has with it's CTS, I'd go ahead and replace it. They don't cost to much, and be sure to get a new O-ring with it. Change it when the engine is cold... really simple to do. You car doesn't overheat when stuck in traffic does it? If so, then you have some coolant system issues (water pump, thermostat, clogged radiator).

Anyone have anything else it could be?

No I don't have access to a VAG-COM and likely won't be in the near future. Too complicated for her to be using by herself (I am at a distance).

Also they mention different colored coolant sensors (green top, blue top)?
Can someone enlighten me on this topic as well.

Thanks!!!

Anyone have any ideas on this?

I Hope U Still Dont Need Help But Get The Green Coolant Temp Sensor Its The Only One You Can Get