Passat 2010 Heater Problems (with climate) & cutting out problems

**asguk** · 13-10-2015,12:05 AM

hi my first post here.

So far no problems with my great 2.0TDI 10plate Passat until now...

Problem 1: Cabin Heater
Only seems to get hot air coming out when on highest fan setting.
All other lower fan setting get hardly any heat coming out. Blows ok but little to no heat.
Car fully warmed up to running temperature

Also when you do select full speed on the blower there is a humming noise coming from passenger side of vehicle it seems, and is very noticeable outside the car too!!
Car has climate if that makes any difference. Aircon appears to work just fine.

Problem 2: Engine Cutting out
This has happened 3 or 4 times.... when slowing down to roundabout or alike, the car seems to cut out. Try restarting by pressing the key to restart, the car seems to want to turn over but wont - almost like battery is flat. But if you remove the key from the dashboard slot, reinsert it and car starts fine.... I'm guessing immobilizer problems but has anyone got any suggestions on this and why suddenly does it?

Had a unit hooked up and no error codes displaying!!

any pointers would be very much welcome...
thanks

**Crasher** · 13-10-2015,09:50 AM

Did you have the HVAC system scanned and what type of scanner was used? These engines cutting out and leaving no codes is USUALLY the crankshaft speed sensor, but not always. It is impossible for it to be the factory fitted immobiliser, it does not work that way.

**DMitch16** · 13-10-2015,12:13 PM

Had a loom short (Turbo and DPF sensor loom burnt onto turbo heatshield) that caused random cut outs and difficult restarts. Also flagged the crank sensor as being faulty when there was nothing wrong with it. Good job I found the short before I got around to trying to change the crank sensor!

**asguk** · 13-10-2015,03:52 PM

Thank you the replies, it went to an independant VAG specialist so not sure but will find out the scanner type they used and let you know. They indicated it could be the immobiliser which concerns me now as Crasher you have said that's impossible. My understanding of immobilisors was they were relevant when trying to start the car, not once it was already started, although you here of cars immobilisers cutting in on motorways etc... So why on a Passat might it be impossible?

Also any thoughts on the heater issue? that's more of a pain than the occasional restart at traffic lights, especially with winter coming. you get a decent amount of heat coming out of vents when on fuill blast., but turn it to setting 1, 2 or 3 and you get hardly any heat.

thanks again for helps so far

**Crasher** · 13-10-2015,05:12 PM

The factory fitted immobiliser only acts during the starting phase where the engine will start and immediately cut, this is stored in the central electrics unit on the Passat, not in the instruments as normal. On the Passat there have been ignition switch issues which is what they may have been referring to, at least I hope so for a VW specialist! I feel that the heating issue may show up with an HVAC code read as being an issue with your flaps.....

**asguk** · 13-10-2015,05:32 PM

Hi Crasher - thank you for the explanation very appreciated.
ON the heating side of things, just feels like you have to have on full heat setting to get anything out, any lower than that seems to be just the same, mainly cold but with a hint of warmth.... I assume by the flaps you mean the devices that divert the heat to the various outlets when instructed and one would assume the is something that regulates the amount of warm air being blown in versus cool air like a valve. Is that a big job to deal with the flappers?

**DMitch16** · 13-10-2015,05:42 PM

Originally Posted by asguk

Hi Crasher - thank you for the explanation very appreciated.
ON the heating side of things, just feels like you have to have on full heat setting to get anything out, any lower than that seems to be just the same, mainly cold but with a hint of warmth.... I assume by the flaps you mean the devices that divert the heat to the various outlets when instructed and one would assume the is something that regulates the amount of warm air being blown in versus cool air like a valve. Is that a big job to deal with the flappers?

Most likely to be the mechanisms that move the flaps i.e. motors, solenoids etc. Flaps don't often jam but I have seen such in my time (cheap plastic these days).

**asguk** · 13-10-2015,05:55 PM

Originally Posted by DMitch16

Most likely to be the mechanisms that move the flaps i.e. motors, solenoids etc. Flaps don't often jam but I have seen such in my time (cheap plastic these days).

thanks for that and your previous comment sounds like need to get scanner back on it and see what codes come up and I've read somewhere it can do a reset of the flaps too just in case they're out of sync.

**Quatrelle** · 13-10-2015,07:47 PM

Complete shot in the dark (and I might be thinking about another forum

) but was there a thread here some while ago about a failed resistor in the heater control such that it would only work correctly on the highest setting?

Apologies if that's a bad guess.

**asguk** · 13-10-2015,08:26 PM

hi - yes seen similar posts, but i assumed they related to the blower fan not working on anything but the highest setting. Blower side of things on mine works fine, its the heat only really comes out when on "Hi" setting. anywhere else on the temperature dial, you just get cold/luke warm air coming out.

Also when blower on full power "4" I can hear a buzzing/vibrating sound from under dash but also from outside the car too...