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View Full Version : Passat 06 TDI - vibration under bonnet after engine turned off



stoo
08-08-2007, 11:26 AM
Need some help from fellow passat drivers as I suspect VW are telling me porky pies! :mad:

For the last few months everytime I turn my car off after a journey, it makes a weird vibrating noise under the bonnet about 3-5 seconds after the engine is switched off.

It's been in to VW who say it a control unit full of relays which switch off a few seconds after the engine has been stopped. When I told them it never use to do it, all they could say was that they've tried 3 other passat's in the workshop and they all do the same and it a known issue!!! Yeah right!

So... does anyone else suffer from their car making weird noises after they switch it off??

Quatrelle
08-08-2007, 07:33 PM
Aircon fan?

passat170
09-08-2007, 02:42 AM
I've had so many porky pies and now I'm full to the point of being sick all over the dealers forecourt!
And I've also had "we've tried another Passat and it's just the same".
Believe you me they are well trained in doing this! Just to make you feel that your car is normal like the rest of them!
I'd be interested to know why these relays are operating for 3-5 seconds after you have switched off.
Can't help any more though I'm afraid.
Cheers,
J

stoo
09-08-2007, 07:02 PM
cheers Quatrelle and passat170.. I don't think it's the aircon fan unfortunately, it's not a wirring noise more of a honnnn (hard to describe but like a honk without a K!).. Anyway it's booked in to change the convienience control unit so I'll see if that helps next week.. Somedays I just want my subaru back!

What's the 170bhp go like by the way? I wonder what the difference is on the road!
cheers...

passat170
09-08-2007, 11:49 PM
Hi stoo,
The 170 TDI Passat (mine with DSG) is superb!
I can be driving along, switch down with the paddle shift without the wife even realising I've dropped a gear, and fly past Sunday drivers!
The only thing I don't like is the kick down like all auto's have..... the torque these engines have is superb and it's not always necessary to rev the engine up to accelerate quickly. If you put your foot to the floor it kicks down and revs like hell - yes it shifts but if it didn't kick down it would still pull like hell! And the sports mode lets the engine rev highly before changing gear.
So I would like a setting in between normal and sports mode that doesn't allow kick down and lets the torque pull you away!
Last night I put my foot right down and it is quick and exhilarating but this upsets my wife who prefers it a little more gentle in the car!
I have been looking at Subaru's recently (given the disgraceful experience buying this Passat from the devious and dishonest UK dealer and my currently unresolved cruise control fault). They are nice cars and reliable but I would have to go back to petrol and a handbrake and in my old age I don't want one of these old fashioned levers again and I have become so used to superb TDI torque and low down pulling power.
I have previously bought a Golf 110 TDI, Golf 115 TDI and a Golf 130 TDI new from Holland, personal imports, and have benefited from absolutely superb service and prices over there. Given the current exchange rate it wasn't viable to get my Passat from Holland but if/when the exchange rate gets better I will gladly advise anyone who wants to personally import.
These Passat's are nice cars, superb design, superb build quality, superb ride quality, superb performance and fuel economy, reliability could be improved but UK service is disgraceful. My Sept 07 Passat had a noisy solenoid operated wastegate valve from only a few weeks old (now replaced) and these niggling reliability issues are generating a significant revenue stream for dealers repairing cars off warranty. Sitting around at the dealers waiting for them to come back and tell me they can't diagnose the fault with my cruise control (when they can see the fault driving my car and I can't blame the dealer if the diagnostics don't find what I suspect is a software design / coding problem) I was amazed to hear the conversations when people were picking their car up or phoning in after repair (a replacement solenoid operated wastegate valve replaced after the warranty has expired will cost you around £145, a replacement throttle position sensor (as these are drive by wire) will cost you around £250 but these shouldn't be going wrong). You wouldn't expect these problems with Toyota's and if Toyota designed a stylish car and a diesel with an auto I might have one! And this last message is for the person who posts on here saying "If VW made fast cars I'd still buy a Toyota".
Hehe!
Enough waffle for now, hope you get your car fixed, let us know!
Cheers,
J

MAC
14-08-2007, 01:08 AM
Stoo,

If it sounds something like a spring "twanging" or "boinging" several seconds after the car is switched off, we have the same thing on our '06 2.0l TDI Sport. I thought it may be something to do with the fuel pump? To be honest, I have never thought to ask about it, but as mine is currently in for the new convenience unit / ECU fitting I'll make the enquiry when I go to pick it up on Tue / Wed. I'll let you know what they say.

Meanwhile I'll make sure I listen out for it on the '07 2.0l TDI Sport they have loaned me.

Mark

passat170
14-08-2007, 09:56 PM
MAC, for information it would be useful to know why your convenience unit and ECU are being replaced.
Cheers,
J

MAC
14-08-2007, 10:03 PM
J,

I'll get the low down when I go and pick it up hopefully on Wednesday.

For info, the loan car doesn't exhibit the same noise as mine or Stoo's.

Mark.

MAC
17-08-2007, 07:55 PM
J,

The convenience unit has been re-called due to an apparent potential for the ECU to shut things down (so I was told yesterday).

The steering re-call is for the steering rack, not column, as there has been cases of the internal seals leaking.

The "boing" / "vibration" after switching off is apparently something to do with the air-con, and some motorised flaps??. The guy on the service desk told me that VW know about it, but havn't issued a cure as yet, so they were only allowed to adjust the flaps in my car. Incidentally, the noise has not gone away, and is heard 18 seconds after switching the car off.

Regards

Mark

Quatrelle
17-08-2007, 10:15 PM
18 seconds! I can hear my aircon fan running down as soon as I turn off the ignition - even after a run, like the other day, in an air temperature of 34 deg. I'll have to stand around and have a listen next time....

MAC
18-08-2007, 07:36 AM
Quatrelle,

It's not the air con fan, as like yours, mine runs down straight away after switching the engine off. The noise is well after everything has shut down, hence the 18 secs. The loan car that I had whilst mine was in for the recall did not have the noise, so I guess it doesn't affect all cars. But as I mentioned earlier apparently VW now know about it but don't have a "fix" as yet.


Mark

Quatrelle
18-08-2007, 06:14 PM
Mac,

I'm wondering if I shouldn't keep out of some of these threads, seeing as mine's lhd - apart from the engine, there must be quite a few differences under the bonnet regarding layout etc.

I haven't had need to take the car back for anything (yet!) but the French dealership has seemed very up front on the couple of occasions I've been back there (for recalls).

stoo
21-08-2007, 07:20 PM
hey everyone..

Many thanks for the replies! Well I've had the convienience control unit changed and it's made no difference at all.. Same stupid noise happens every time I switch it off! The mechanics do seem to have heard of this before but still can't fix it. They swear it is a bunch of relays which switch off 3-5 secs after you switch the car off. When I asked them why it didn't do it when I first owned the car for the previous year, VW simply replied they don't know.

This is not going anywhere fast unfortunately. At least whilst they had my car they bothered to change the Steering ECU for some other recall.

The only upside is they have given me a decent bottle of champagne for my troubles but I'd still rather the car didn't fart everytime I switch it off!

I might have a play with the air-con - on/off, hot/cold etc before I switch it off and see if that makes any difference!

thanks again, Stoo

MAC
21-08-2007, 07:40 PM
Stoo,

As my reply says earlier, I think the dealers are waiting for an official repair from VW. Mine is still doing it, but the loan car didn't. Also, like yours, mine didn't make the noise when I first got it. I'm going to ring my dealership up again later this week to let them know mine is still doing it, and see where I go from there. If I get any joy I'll let you know.

Mark