fault p1031

mrbroons

Well-Known Member
It would be interesting to know what you observe on your current one, (with a suspect N316 valve), when running the Output Test.
Mac.
Sure thing, sorry been busy with other projects, I'll get back on this soon and will definitely report back what I find. I'm pretty sure the Actuator is ok, it is likely the feed to the solonoid that is fault, but I'll continue with the test and post what I find.


Intersting video.
 
Best to avoid that manifold in those cars he mentioned! At least our manifolds are alloy and we can change the parts that can't be replaced in the above video ie N316 valve etc.
 

lfield

Member
Is that running on residual vacum, from last time the engine ran? If so, it also proves the non- return valve is good, I think ...
Mac.
Yes, this is residual vacuum. As far as I understand, the engine must be off for the Output Tests to run.
 

PlasticMac

Member
That's what I read in your Rosstech post. Just wondering how long the residual vacum remained after the engine was switched off.
Can't decide if the non-return valve is in the vacum circuit, or the vent side. Looking at those self study notes, I think it's the vent side ...
Mac
 

lfield

Member
That's what I read in your Rosstech post. Just wondering how long the residual vacum remained after the engine was switched off.
Can't decide if the non-return valve is in the vacum circuit, or the vent side. Looking at those self study notes, I think it's the vent side ...
Mac
From what I observed, as long as the vacuum can be physically maintained i.e dependent on the leak rate. I didn't have the patience to wait but there is nothing that purges it within a few minutes of the engine stopping. When the ignition is switched on, it is purged and you can hear the "FSI click". It is music to my ears everytime I sit in my FSI. It means the vaccum is good, my flaps are moving and most importantly I am in an FSI. :)
 
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Gilbertd

New Member
New owner with what seems to be an old problem. Just picked up a 2004 1.6 FSI with the MIL on and the P1031 fault showing. Previous owner told me that he had replaced the vacuum actuator with a brand new one but the MIL would still keep popping back up. Cleared the fault and drove about 30 miles, no problem. Stopped to fill it with fuel (near Derby and got accosted by another A2 owner!). Started the engine and the MIL was back. Drove fine but at around 75-80 mph, I could feel the power coming and going as if the flap wasn't connected to anything so was moving as and when it felt like it. Having got it home had a better look. Taking the vacuum hose off the actuator and there was stored vacuum there so no leak. Put a pipe on the actuator and tried sucking on it and the actuator arm moved. Made sure the vacuum hoses weren't perished and pushed fully home but couldn't find anything obvious so tried driving it. As soon as I pulled away the MIL came back on, cleared the code and it drove perfectly. Could even feel it doing it's stuff and giving me a kick as soon as it hit 3,000 rpm. Drove it for around 20 miles and it seemed that I had cured the problem. Until the next time. As soon as it was started again, the MIL was back on with the same code.

So, I can clear the code and it will drive perfectly but as soon as the engine is switched off and back on again, the MIL is back and the same code is thrown. When the MIL is off, it appears that it is working fine, so why doesn't it like being switched off? Any clues?
 

chrisnic

Member
I was led to believe that after clearing codes, if the fault is still present, then it will trigger the EML after 3 starts...!!!
 

PlasticMac

Member
This might explain:

"One more interesting observation is that when the engine is switched off, the flaps stays activated. It is not until you switch the ignition on again that the vacuum is released and the flap returns to the non-activated state. Listen for the sound when you switch on the ignition, you can hear it. See the video of this that Andy posted previously. I wonder how many FSI owners know about that noise? The good thing is that this gives us a good way to test for vacuum leaks. I recon with some Tipex, a small nail and a multi-meter and could now diagnose any p1031 problem"

It's from a post on the previous page of this thread, courtesy of @Ifield

Mac.
 

Andrew

A2OC Donor
When the MIL is off, it appears that it is working fine, so why doesn't it like being switched off? Any clues?
First of all welcome.

I assume you have read and digested this thread, there is a lot of information and the latter half has greatly increased my understanding of the function of the FSI flap problem and diagnosis, it has been quite enlightening.

As to your question, it is not switching the engine off that causes your problem, the problem arises when you next start the engine. Believe it or not between the two when the car is not in use the vacuum system keeps the flaps shut. When the key is inserted and turned to the first position the vacuum is released (I can hear a click which I am guessing is the N316 valve and apparently you can hear (I have not had chance to seriously listen) the vacuum release. Whatever, with the lack of vacuum the flap rod spring opens the flaps. A further turn of the key and the engine starts to reinstate the vacuum to shut the flaps at idle. Thus in the startup process the flaps have traversed from fully open to fully shut and if the ECU detects from the flap potentiometer (it reports flap position) this has not occurred you get the EML and the dreaded fault 'Setpoint not reached'.

Hope I got this right!

Maybe more later.

Andy

Edit. Actually the click on ignition turn is more likely the vacuum actuator opening flaps as it sounds like the click of the actuator being exercised in the video above,
 
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PlasticMac

Member
Wondering, if the car is unused for a while, the vacum will, eventually, leak away, and the flaps will open (by return spring). In this case, does the controller instigate a flap test cycle (close open close), at next engine start up, or will the controller wait until the engine next exceeds 3000 rpm?
If the latter, it would fit the reports of the EML warning not coming on straight away, after the fault has been cleared (with VCDS). Keep under 3000 rpm, and no EML perhaps?
Mac.
 

Gilbertd

New Member
That would make sense and explain why the MIL came on as soon as I pulled away after having let all the vacuum out of the actuator to check the pipes. What I didn't check was whether it moved when I pulled the pipe off (no tippex so a black plastic arm moving in a dark place isn't that obvious). I don't have VCDS, just a generic code reader, although I do have an interface and Vagcom somewhere, I'll try that next time I'm with the car (tomorrow). As I bought the car for someone else, I doubt she will ever exceed 3,000 rpm to be perfectly honest. Having previously bought an A2 for another relative, I knew that they are reliable, economical, comfortable and don't rust, so when asked to find a car for someone else, knew what to go for.
 

Andrew

A2OC Donor
Hi Mac,

I thought about these two points as well.

1. I cannot see the vacuum lasting 'forever' or at least a long period of weeks/months. Regardless if a is vacuum is present or not I guess the vacuum is purged as part of normal startup (if it needs it or not), after all it does not matter if the vacuum has leaked away or purged as part of startup the end result is the same = no vacuum.

2. The delayed EML. When clearing the fault with the scanner I assume the ignition is turned on, which will have purged the vacuum and I wonder if by clearing the code the ECU has lost 'sight' of the open set point and the flap integrity check. If the engine is now started, without removing ignition key, and the car driven normally the ECU has no reason to light the EML, hence the delay. It would be interesting to know if the fault returns immediately at startup if the key is removed after fault clearance and then the engine started Sorry put that in a cumbersome way and probably a redicoulus theory anyway!

Andy
 
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Gilbertd

New Member
Update is it looks like it has a very slight vacuum leak. Marked the actuator rod (couldn't find any Tippex so used a fluorescent marker and UV light). After it has been run, the actuator rod is pulled fully up but after leaving it for half and hour or so, it has dropped. Pulls fully up as soon as the engine is started. Having cleared the code before checking it, the MIL came back on within 100 yards or so but if I cleared it without stopping the engine, it stayed off and seems to be working fine. Until it was next switched off for more than a couple of minutes. So I assume it is losing some of the vacuum, although not all of it as there was vacuum there when I pulled the hose off. As it has a new actuator, I'm wondering if it is a pattern part that may not seal as well as an original? Are cheapo pattern parts available for Audi? I know that for my Range Rover I can buy original, OEM and Britpart, the Britpart ones usually have Sh substituted for the Br.......
 

PlasticMac

Member
I'm thinking that the Close - Open check on the flaps is only initiated by ignition On.
This prompts vacum release, and flap to open, via return spring. Engine Run creates vacum, and flaps (should) close, and Set Point is reached, and so no EML. Flap movement is monitored all the time, but (maybe) only has potential to trigger EML at next Start sequence.
Does this fit your observations?
Mac.
 

Gilbertd

New Member
After it had been left and the flap had opened, switching the ignition on did nothing but the flap closed the instant the engine started and vacuum was generated. So no Close - Open check although this may be because there was insufficient vacuum to close it or it may be because the fault code was pending so it didn't try to do it.
 

PlasticMac

Member
As Andrew has said, since the vacum is released (via N316 valve) by switching the Ignition On, it makes no difference if the vacum has already drained away. If any vacum is still present, switching the Ignition On will immediately vent it via the N316 valve, you may see/hear this venting and the actuator/linkage move. If there's no residual vacum, the N316 will still open, but you'll see/hear nothing (except the N316 click), as there is no vacum to vent, and the flaps have already been opened by the return spring (as the residual vacum drained away)
When the engine runs, vacum is created, the N316 closes, the actuator moves, and the flaps (should) close. I think this fits with what you saw ...
Mac.
 

Andrew

A2OC Donor
@Gilbertd

Pleased for your progress, well done for spotting the vacuum leak with the actuator arm extending over time with engine off, another useful check to perform in diagnosing the cause of 'Set point not reached'. Tippex takes me back 30 years but I still have a little pot that amazingly is still liquid (just) and I will try the test tomorrow as long as not raining to see what happens with my FSI.

Edit. I wrote the previous paragraph last night but it got late and I went to bed, never completing the rest of the post and thought I would come back to it today. Bad news, I have since had chance to do the Tippex test and my FSI does exactly the same, the actuator arm slowly moves out of the actuator over time when the engine is off. I checked after half an hour to compare with you and the arm was full extended, in fact I did it again and it had moved down completely after only 15 minutes when I looked. Looks like this is normal FSI behaviour, but it would be good for a third party to confirm, your problem is not a vacuum leak it seems.

You ask about the vacuum actuator, part number 036129061A. A quick google search by part number suggests, but it was quick, there is only one brand available, Vaico, who claim to be an oem supplier. About £90 from the usual parts websites.

Suggest your next step is monitor flap behaviour with VCDS as per my post #68 and post the results.

Andy
 
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PlasticMac

Member
I agree with Andy,.monitor flap movement with VCDS.
If you utilise the *suck it and see" method, with a clamp to close the tube, once the actuator has moved to closed, you'll be able to check the integrity of the actuator's diaphragm. Other than the tube itself, a vacum leak will be the actuator, the non return valve, or the N316 valve I think.
Mac.
 
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