fault p1031

mrbroons

Well-Known Member
Neg of multimeter to ground.
Mac.
I'll give it a go when I can get in there. It looks like I need to remove the high pressure fuel rail to get access is that correct? Presume it is pull the fuse on the high pressure pump and run the car until pressure is nominal on measuring block 140?
 

lfield

Member
I'll give it a go when I can get in there. It looks like I need to remove the high pressure fuel rail to get access is that correct? Presume it is pull the fuse on the high pressure pump and run the car until pressure is nominal on measuring block 140?
No. Just remove the air duct out of the way. The top of the pug will clip off. Get a thin nail or pin and push in next to the wire until it stops.
 

lfield

Member
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.
 

mrbroons

Well-Known Member
Im at the car now. Ive got a camera on the rod so I will record any motion etc.. I may live stream it if there is interest?
 

mrbroons

Well-Known Member
Im at the car now. Ive got a camera on the rod so I will record any motion etc.. I may live stream it if there is interest?
Looks like I have to wait 24 hours for streaming on Youtube, but this may be a good idea if people are up for it?
 

mrbroons

Well-Known Member
I'm afraid my skills doing this in small spaces are somewhat basic to say the least. I have spent my time removing components. So..... Removing the drivers side headlight, which in turn gives better access to the lower clamp for the air inlet pipe has helped a lot. I have also removed the retaining clamps for the high pressure fuel pipes and move them slightly out of the way.

I have now tested the actuator with some piping that I got from Halfords this evening and I can confirm the actuator works exactly as expected when subjected to suction!!! So this is a win! I'll get on with testing the pot now and then I'm left with the solenoid I believe, and the vacuum hoses themselves.
 

lfield

Member
I have now tested the actuator with some piping that I got from Halfords this evening and I can confirm the actuator works exactly as expected when subjected to suction!!! So this is a win! I'll get on with testing the pot now and then I'm left with the solenoid I believe, and the vacuum hoses themselves.
Great! The sucking tip from @PlasticMac is invaluable. It saves us from needlessly removing the lower intake manifold.
 

lfield

Member
I have a reply from Ross Tech. The voltage is (as I assumed) the Intake Manifold Flap Valve potentiometer offset voltage. They also said:

VCDS can test the N316 with the [Output tests], the N316 should click on/of for about 50 seconds. The engine must be off for the [Output Tests] to run.
 

mrbroons

Well-Known Member
I have run the output tests and nothing happens. When I have run these previously (on another car) I have seen the rod move up and down. So on this car the output test is a fail.

So in terms of offset, I assume this value should not change then as it is the adaption of the what the potentiometer is reading to the actual movement of the flap on the car?
 

PlasticMac

Member
Earlier, using the "Suck Test" you saw movement (maybe not full scale, but movement all the same) , of the actuator, etc. And, no vacum also?
So, I'd suggest you see info from Rosstech, courtesy of @Ifield, and check the N316 valve next:

"VCDS can test the N316 with the [Output tests], the N316 should click on/of for about 50 seconds. The engine must be off for the [Output Tests] to run"

Onwards and upwards, (or, in this instance, probably sideways!)

Mac.
 
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