Automatic recirculation HVAC fault - doesn't switch on poor air quality

[prise]

UPDATE

I dropped the car off today and was called back 4 hours later to say it was they had been able to perform the test this time with advice from head office and the the system appeared to be working correctly. I asked how the system had been tested and was told that the official test procedure involved the use of a small amount of LPG to trip the sensor. I was also told that they had performed the same test on a new vehicle to confirm that it switched to recirculation in the same way. I have no knowledge of the test procedure they used so I don't know if it is able to test the sensitivity of the sensor or whether it only tests for functionality.

The customer service rep had no explanation for why the system doesn't go to recirculation when driving behind badly smoking exhausts (burnt oil and petrol smell) so given they diagnosed a different fault first time round and then concluded on the second visit that it was working correctly I have concluded that they were not familiar with the system and the test procedure.

Is the air quality sensor only useful if I drive through a gas leak!

[Maverick]

I dropped the car off today and was called back 4 hours later to say it was they had been able to perform the test this time with advice from head office and the the system appeared to be working correctly. I asked how the system had been tested and was told that the official test procedure involved the use of a small amount of LPG to trip the sensor. I was also told that they had performed the same test on a new vehicle to confirm that it switched to recirculation in the same way. I have no knowledge of the test procedure they used so I don't know if it is able to test the sensitivity of the sensor or whether it only tests for functionality

The customer service rep had no explanation for why the system doesn't go to recirculation when driving behind badly smoking exhausts (burnt oil and petrol smell) so given they diagnosed a different fault first time round and then concluded on the second visit that it was working correctly I have concluded that they were not familiar with the system and the test procedure.

You can conclude whatever you want but they told you the Volkswagen method of testing the sensor for operation which they performed so I'm not sure what else you want them to do short of fly the sensor to the manufacturer for testing the same way.

Is the air quality sensor only useful if I drive through a gas leak!

No but it's not some magic sensor that works like you expect it to. A basic portable hand held gas detector starts at around $1500 and they can easily reach $6000+. The sensor in the Golf sells through the dealers for under $150.

Information on how the sensor operates is here - Climatronic Air Quality Sensor Operation and Location

[hooba]

The sensor in the Golf sells through the dealers for under $150.

$150!! Another bloody VWA parts rip off!!

I can get an LPG sensor for less than $1.



Come on Mav, give us at least one smiley!

[logger]

Here I'll give you some hooba


I find the auto recirc system to be gimmick and do not use it much. It is too slow to react and by the time it has switched I have copped a lungful. So I tend to select the manual recirc in the same maner as I would wind a window up before entering a tunnel or pulling in behind a dirty truck.

Prise, Bummer they cannot fix your system to your satisfaction. What makes you say the Auto recirc is not working? Mine just shows a Car Icon with the recirc arrow in it with "A" beside it. But there is no way to tell if the system has set itself to fresh or recirc onced in this setting. So could it just be that, because it is reactive and not predictive, you are also copping a lungful before it switches, leading you to believe it is malfunctioning.

I just hooked mine up to VCDS, looked at the recirc and air quality status. Started the car with AC in Recirc Auto and it indicated "recirc mode due to air quality" almost instantly and I could see the recirc valve close in VCDS. But then I turned the car off and did the same thing a couple of minutes later. Again in Recirc Auto. This time it did not sense bad air and indicated fresh. After two or three minutes with the engine running in the garage and well on the way to gassing myself it still had not switched. So I gave it away as it was getting way unsafe. Dunno if this was effected by logic related to start cycle and temp. Who knows but it would have readily let me gas myself before going to recirc. Gimmick I reckon.

[mfl]

Prise, Bummer they cannot fix your system to your satisfaction. What makes you say the Auto recirc is not working? Mine just shows a Car Icon with the recirc arrow in it with "A" beside it. But there is no way to tell if the system has set itself to fresh or recirc onced in this setting. So could it just be that, because it is reactive and not predictive, you are also copping a lungful before it switches, leading you to believe it is malfunctioning.

Gimmick I reckon.

Prise, I understand where your coming from, I also like things to work in cars they way should, the smells have only started coming into my car in the last month and before then it seemd to be working fairly well, now I just hit the manual recirculation button. pity there is no indication as to what the system is doing.

As my car is in for other warranty repairs on Thursday (again), I am getting them to check the system out, see what they say

[mr gee]

Here I'll give you some hooba


I find the auto recirc system to be gimmick and do not use it much. It is too slow to react and by the time it has switched I have copped a lungful. So I tend to select the manual recirc in the same maner as I would wind a window up before entering a tunnel or pulling in behind a dirty truck.

Prise, Bummer they cannot fix your system to your satisfaction. What makes you say the Auto recirc is not working? Mine just shows a Car Icon with the recirc arrow in it with "A" beside it. But there is no way to tell if the system has set itself to fresh or recirc onced in this setting. So could it just be that, because it is reactive and not predictive, you are also copping a lungful before it switches, leading you to believe it is malfunctioning.

I just hooked mine up to VCDS, looked at the recirc and air quality status. Started the car with AC in Recirc Auto and it indicated "recirc mode due to air quality" almost instantly and I could see the recirc valve close in VCDS. But then I turned the car off and did the same thing a couple of minutes later. Again in Recirc Auto. This time it did not sense bad air and indicated fresh. After two or three minutes with the engine running in the garage and well on the way to gassing myself it still had not switched. So I gave it away as it was getting way unsafe. Dunno if this was effected by logic related to start cycle and temp. Who knows but it would have readily let me gas myself before going to recirc. Gimmick I reckon.

Interesting that you tried a quantitative way to assess the sensor. I had my car serviced in June and the cabin air filter was changed. I thought I smelt more outside pollutants with the new filter and thought perhaps VW had replaced them with a plain filter. But I was wrong, the new filter is carbon impregnated. Looks like I need to look at my VCDS as well.

Did you notice if the sensor can be coded for more sensitivity?

[logger]

Did you notice if the sensor can be coded for more sensitivity?

I do not think so. However I did notice that the default coding of these units is set to indicate the sensor is not installed, when it is. Checked someone elses coding as well.

Would have expected bit 0 to be checked, however as you can see it is not. The coding would then be 0100000000 instead of 0000000000. However I am not familiar with the system. There could be a reason for it being set this way. ie inbuilt sensor versus remote sensor. One requiring coding the other not, or Ross-Tech could have their decode rrrs about.

[prise]

You can conclude whatever you want [/URL]

First visit - I'm told it is faulty and they have some indeterminate connectivity fault and will require the car for 3 days
Second visit - phoned 3 hours after dropping it off and told everything is working properly and the tech had talked to head office about it.

Reasonable conclusion - they didn't know how to test it the first time.

Look, I'm not having a go at the dealer (I am happy to keep using them). They appeared to be up front about it, had a loan car on offer and answered my questions to the best of their ability. Cars are becoming increasingly complex with all the features that get added each year so I accept they will sometimes take more than one go to work things out.

[prise]

What makes you say the Auto recirc is not working?

I drove behind an absolutely foul exhaust for over a minute (not diesel smoke) and the system did not switch to reirculating. I am familiar with the change in fan noise that occurs when recirculation is selected manually and I definitely didn't get the change until I gave up waiting for it and selected recirc myself.

Now the foul exhaust may have been predominantly burning oil but it was also running very rich so no shortage of HC's

Going through the Burnley tunnel yesterday I detected it switching just before I exited the tunnel so I agree with it being a gimmick. From what I've read car manufacturers are using a cheap (to them, not to us if Maverick is right about the $150 price) MOS sensor.

[logger]

Fair enough. Not working well at all. BTW, I was not for minute doubting you when I asked. Was just wondering if it was your nose or some indication on HVAC that was telling you was not working as it should.