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Chat Area => General Car Chat => Topic started by: Webby the Bear on 11 October 2014, 12:44:40

Title: VW Passat trouble codes help
Post by: Webby the Bear on 11 October 2014, 12:44:40
Hi guys,

Just put the code reader on the wife's dad's Passat (engine code AJM). Got the following:

(http://i1226.photobucket.com/albums/ee402/webbybear1/vwpassatcodes_zps4d526fa1.jpg) (http://s1226.photobucket.com/user/webbybear1/media/vwpassatcodes_zps4d526fa1.jpg.html)

A quick Google search has thrown up some interesting replies.... one is checking vacuum hoses... I checked them manually and cant find any issues. Another thread says N75 valve is fekked.

Os, the MAF code.... new MAF?

Anyone know? :)
Title: Re: VW Passat trouble codes help
Post by: 4x4 on 11 October 2014, 12:47:24
Try cleaning maf 1st and see if that helps  :y
And clear codes before refitting it.
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 11 October 2014, 12:50:20
Thanks Martin, will do  :y

Got a feeling its the top code that's the real problem. Note the car has ZERO power lol

Should I also pop that front hose off to geta look at the turbo...

(http://i1226.photobucket.com/albums/ee402/webbybear1/vwturbo_zps90f6284d.jpg) (http://s1226.photobucket.com/user/webbybear1/media/vwturbo_zps90f6284d.jpg.html)
Title: Re: VW Passat trouble codes help
Post by: 4x4 on 11 October 2014, 12:55:18
Are them vacum hoses braided rubber?
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 11 October 2014, 12:57:20
I think they're braided. They're not the normal rubber oneslike on the omega
Title: Re: VW Passat trouble codes help
Post by: 4x4 on 11 October 2014, 13:00:10
They may look ok,but for the age of the car i would replace them with silicone  :y
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 11 October 2014, 13:03:24
ok thanks mate. for the sake of a few pence I may just do that  :y

looking at the articles on the internet ive got a feeling it may be this n75 valve. but obviously need to confirm that cos I think its quite expemsive
Title: Re: VW Passat trouble codes help
Post by: 4x4 on 11 October 2014, 13:05:25
http://www.vwt4forum.co.uk/showthread.php?t=87750
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 11 October 2014, 13:42:07
Thanks Martin.

Here's the bad boy in question...

(http://i1226.photobucket.com/albums/ee402/webbybear1/vwpassatn75_zpsc9a13865.jpg) (http://s1226.photobucket.com/user/webbybear1/media/vwpassatn75_zpsc9a13865.jpg.html)

Got 37 ohms resistance and got supply voltage. The link doesn't list the spec of the AJM engine code but I'm assuming I have the higher resistance one.

Am I right in thinking that these can fail even if the resistance is correct? And that failure comes down to a clogged turbo vane(s) thus I should still check the turbo itself.

One oddity I found was that where one of the braided lines from the N75 clips to the plastic retainer it seems quite worn (but no notable holes). I squeezed this with engine running and engine note changes.
Title: Re: VW Passat trouble codes help
Post by: 4x4 on 11 October 2014, 13:49:40
Change that pipe then,and then see if it does the same after.
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 11 October 2014, 14:03:33
Thanks Martin.

Here's a gret reply from someone off one of the forums...

04 1.9tdi fault codes + loss of power until engine - puggered 
engine management light on again, fault codes read (manufacturers)

 18062 electronic instrument panel p1654 intermittent

 17957 control valve boost pressure - n75 open circuit / short with ground. p1549 intermittent

 18080 cooling fan control 1 open circuit / short with ground p1672 intermittent

 19586 egr system control range exceeded p3130 intermittent

 17964 turbo pressure control - control limit below minimal level p1556 intermittent


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Tue 3 Jun 2008 18:24  Back Top End
04 1.9tdi fault codes + loss of power until engine - Screwloose 

 That's better. There's my old friend 17964. [Him and his mate '965 make the trade millions.]

 As suggested; start with the turbo wastegate vacuum solenoid. It should read about 14-20 Ohms across the terminals. If it doesn't - bin it. If it does - check the wiring.

 Then check the operation and cleanliness of the EGR valve - could be stuck open and venting boost pressure.

 The instrument pod one is a "reflection" code; check the real one in the pod's own memory - could be the oil level sensor; if so, check the bonnet catch switch isn't adrift.

 After fixing all those; [the cooling fan isn't part of the limp-home, but check it and it's relay anyway] re-try it and hope 17964 has gone - if it returns, it'll likely need the turbo actuator checking for stiffness, or the turbo off and the vanes cleaning - don't fit an exchange turbo. 
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 11 October 2014, 14:04:03
In short I think I should be checking that turbo also...
Title: Re: VW Passat trouble codes help
Post by: 05omegav6 on 11 October 2014, 14:08:30
If that hose makes a noise when you squeeze it, it has a hole in it.

Change it.

Then report back.

Simples :-*

If the vacuum system doesn't work properly, then the sensors won't work accurately because they can't tell what is happening.
Title: Re: VW Passat trouble codes help
Post by: henryd on 11 October 2014, 15:09:59
Another thing you can try Webby before you get stuck too far in is to disconnect maff sensor and drives the car,it'll run a lot better without it than it will with a breaked one connected,thatwill throw a code up which you delete with yer tool :y
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 11 October 2014, 18:18:31
Thanks guys!

I'm sure I have some thin diameter vacuum line knocking around.

I'll also disconnect MAF and see what I get  :y
Title: Re: VW Passat trouble codes help
Post by: tidla on 11 October 2014, 21:39:18
Have you checked the actual rubber turbo hoses?

Had that code when the vehicle "popped" the large turbo hose by the alternator (below the fuel filter, which was the cause)

There`s two sensors, if there`s a pressure difference between the two ( a big hole in the pipe which doesn't always make a noise) then it will throw that code.

Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 12 October 2014, 15:25:40
Update.

MAF sensor unplugged. Car now flies  :) :) :) :)

Oddly though the CEL didn't come on when driven  :-\

I've cleaned it thoroughly with contact cleaner. Going to recommend a new one if it doesn't drive well with it plugged back in.

Could he drive round with it disconnected until he can afford a new one? I presume with no MAF reading the engine reverts to a default setting?  :-\
Title: Re: VW Passat trouble codes help
Post by: 4x4 on 12 October 2014, 15:29:00
Have you connected maf back up now its clean?
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 12 October 2014, 15:30:37
Have you connected maf back up now its clean?

Yes mate. Going to give it 20 mins for the contact cleaner to evaporate and give it a test run  :y
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 12 October 2014, 15:35:34
Pps, been looking in to this VNT (due to me only knowing the basics I assumed all turbos had wastegates).

in this pic...

(http://i1226.photobucket.com/albums/ee402/webbybear1/vntactuator_zps9972a296.jpg) (http://s1226.photobucket.com/user/webbybear1/media/vntactuator_zps9972a296.jpg.html)

...is the round silver diaphragm looking thing on top of the turbo with vac line.... is that the VNT actuator?
Title: Re: VW Passat trouble codes help
Post by: 4x4 on 12 October 2014, 15:43:29
Waste gate actuator which i presume is operated by the n45 electronic valve
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 12 October 2014, 15:45:23
Waste gate actuator which i presume is operated by the n45 electronic valve

 :y
Title: Re: VW Passat trouble codes help
Post by: henryd on 12 October 2014, 16:37:45
Waste gate actuator which i presume is operated by the n45 electronic valve

No wastegate on AJM motor,variable vane jobby,what you see is the vac actuator :y

Airflow meters not expensive even from VW,circa 65quid ish
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 13 October 2014, 13:25:24
Ps, guys. not bumping the thread but i been looking in to different types of turbos. these VGT (or VNT) ones seem to be the best available.

Is that still the case? Bearing in mind her dad's car is a W reg with a VNT in?
Title: Re: VW Passat trouble codes help
Post by: Webby the Bear on 13 October 2014, 13:26:33
And just to clarify....

the N75 valve uses vacuum to actuate the change in turbine vane angle when required between the lower and higher engine speeds????