Auxiliary heater working all the time - VW Sharan TDi

First of all - let me introduce myself with 2-3 words as this is my first post in this forum. I'm owner of several cars and all of them are with petrol engines. Just a week ago I bought my first diesel ever - VW Sharan with 1.9 TDi engine (116hp), man. year 2002 with automatic gearbox.

Everything seemed perfect at the beginning - good urban mileage (7.5/100 l/km) very good behavior, very stable work of the engine. Then I took the car for a trip on a highway and noticed a very high consumption - the dashboard computer was showing 10/100 l/km on a highway with 130km/h stable speed with cruise control. When I arrived to my final destination (300km) and turned off the engine I noticed that the build-in auxiliary heater is working and stopped just after I shut the engine off. Surely the engine was on it's optimal temperature after 2-3 hours of non-stop driving.
After this I decided to check the aux. heater every time before shutting off the engine - no matter what was the outside temperature or the coolant temp, the aux. heater was working together with the engine - I'm sure about that because when I put my hand behind it's small exhaust I could feel the hot smoke coming from it. Then I realized that maybe this is the reason for my bad mileage on highway.

I took a VAG-COM cable from a friend of mine and decided to run a diagnostics to check for any problems. The only fault I had was:
Address 18: Aux. Heat Labels: 7M3-815-071.clb
Part No: 7M3 815 071 D
Component: HEIZG. B/D5W 0001
VCID: 3169F34FFBDC81962BD-5072

1 Fault Found:
01407 - Flame Extinguished
35-00 - -

But after I cleared the fault it never appeared again, but the aux. heater is still working all the time. I also checked the readings of the module and everything was ok - all the values were correct, including outside temp, coolant temp etc.

Any suggestions? So far the only solution I could think of is to remove the fuse for the auxiliary heater, but I don't even know which one it is Please help.

Have you seen this: http://wiki.ross-tech.com/wiki/index.php/01407

Not much there but there are a few troubleshooting tips

atl630 said:

Have you seen this: http://wiki.ross-tech.com/wiki/index.php/01407
Not much there but there are a few troubleshooting tips

Click to expand...

Yes, but as I said - this fault doesn't appear anymore after I cleared the module memory... I don't know when was it generated and if the reason for it is the same that makes the aux. heater work without stopping.

If you can't figure it out just put in a switch. Turn it off when you don't need it. Easy.

you could have a bad thermostat and auxilary heater will run alomst the whole time we had the same problem on a 2005 VW multivan 2.5TDI PD and the thermostat was bad the gauge showed 90°C but with VCDS i could see that it only got up to around 80°C so we replace the thermostat and auxilary heater now works like it should.