Hi. 

Fabia 1.6TDI 2011, 133,000 miles, gives me  P2279 Intake air leak error code. I can't find any leaks, but the OBD2 scanner shows the throttle position as 88.6% constantly, even at idle and the throttle actuator at 95%, also constantly. If I clear the codes and drive it hard, it will go for miles without any problem, but as soon as I slow down it throws the fault and drops into limp mode. I am assuming that this process means that as long as everything else agrees with the throttle position, it's happy?  Would the throttle position fault create sufficient airflow confusion to the rest of the system to create the P2279 fault or can anyone suggest an alternative possibility? I can't find anything online that corresponds with this issue.

Thanks for any suggestions.

5 minutes ago, AOwen said:

throttle position as 88.6% constantly, even at idle and the throttle actuator at 95%

 

This suggests a throttle pedal position sensor to me, based off my own experience. However, if I'm wrong then I'm fine with being corrected.

PS. The pedal position varies as it should, MAF/O2 rates are OK

@AOwen I was thinking the exact same thing as @AnnoyingPentium .

If you rev the car up in neutral somewhat, are the revs dropping slower than before? That was the case with mine. Other symptoms I experienced were:

• Uneven idle
• Lack of power
• MPG - or a lack of.
• Issues starting after switching off or stalling.

Of course, without sounding like a TV advert, what you experience may vary.

Absolute pedal position varies from 12% at idle to 80% at full throttle

1 minute ago, AnnoyingPentium said:

If you rev the car up in neutral somewhat, are the revs dropping slower than before? That was the case with mine. Other symptoms I experienced were:

• Uneven idle
• Lack of power
• MPG - or a lack of.
• Issues starting after switching off or stalling.

Of course, without sounding like a TV advert, what you experience may vary.

No, with the faults cleared it drives the same as usual. Starts/Stops fine, normal MPG is difficult to gauge. Following the TV advert theme, unfortunately, at present " Other Fabia's are not available!"

What I'd recommend is getting a second-hand throttle pedal position sensor off the 'bay and/or from a scrap 1.6 TDI of the same age, engine code, part number etc. I did the same for mine, wasn't too bad of a job to replace either, just need patience or try and make do with a lack of it, like me.

 

3 minutes ago, AOwen said:

Following the TV advert theme, unfortunately, at present " Other Fabia's are not available!"

 

Tell me about it! I nearly impulsively bought one at £300 to tide me over when mine was like "nah, not happening"

Just now, AnnoyingPentium said:

What I'd recommend is getting a second-hand throttle pedal position sensor off the 'bay and/or from a scrap 1.6 TDI of the same age, engine code, part number etc. I did the same for mine, wasn't too bad of a job to replace either, just need patience or try and make do with a lack of it, like me.

 

 

Tell me about it! I nearly impulsively bought one at £300 to tide me over when mine was like "nah, not happening"

Yes, I'm thinking it's a trial and error job 🙂 I can't find any logical solution from the information that I have. 😖

Just now, AOwen said:

Yes, I'm thinking it's a trial and error job 🙂 I can't find any logical solution from the information that I have. 😖

 

Process of elimination to rule out things perhaps. Definitely replace the position sensor first however. 

1 minute ago, AnnoyingPentium said:

 

Process of elimination to rule out things perhaps. Definitely replace the position sensor first however. 

Yes, it's surprising that given the plethora of information from OBD2 systems, there are still huge gaps in diagnosis 🤔

1 minute ago, AOwen said:

Yes, it's surprising that given the plethora of information from OBD2 systems, there are still huge gaps in diagnosis 🤔

 

All of this scanning lark merely points you in the direction of things. Shame humans aren't clairvoyant though, it would be smashing when working on these cars.

1 minute ago, AnnoyingPentium said:

 

All of this scanning lark merely points you in the direction of things. Shame humans aren't clairvoyant though, it would be smashing when working on these cars.

Just a thought, if the pedal position is reporting 88% constantly (i.e. full throttle) shouldn't the engine be revving it's little nuts off? Where does the system know to ignore the pedal position signal ?🤔

4 minutes ago, AOwen said:

Just a thought, if the pedal position is reporting 88% constantly (i.e. full throttle) shouldn't the engine be revving it's little nuts off? Where does the system know to ignore the pedal position signal ?🤔

 

Good question. I never measured mine due to the fact I don't have all of this fancy gadgetry, besides a fairly simplistic code reader. There must be something that I'm not fully aware of that cuts the signal somewhere, someone with more knowledge should be able to help more.

Just now, AnnoyingPentium said:

 

Good question. I never measured mine due to the fact I don't have all of this fancy gadgetry, besides a fairly simplistic code reader. There must be something that I'm not fully aware of that cuts the signal somewhere, someone with more knowledge should be able to help more.

Thanks @AnnoyingPentium I am a Mech Eng and used to solving logic problems, but this one just doesn't! 🙂

Intake leak fault under deep manifold vacuum suggests a vacuum leak, don't just use your eyes, give those connections a good pull.

4 hours ago, AOwen said:

I am a Mech Eng and used to solving logic problems, but this one just doesn't!

Unless you know the evil ways of VW computer programs difficult to apply logic.

 

Someone want to apply logic to some electrical faults Ken said battery or charging issue, I as always said battery but the chap just could accept that the machines take over and have their own very invasive and intertwined programs, with no doubt glitches and errors in them.  VW have over-complicated computer systems on these cars (wonder how that could possibly help them, cough).

 

Let your car battery get low and try and make logic out of the scan tool error codes and readings.

 

Apart from that I just say about checking the throttle body and MAF are clean, never overlook the basics and yes use your eyes, hands, nose, ears and why trust one machine a scan tool against another like VW's finest .  Cross reference all findings and information - especially when it's from me.

 

Better scanners give loads more info and I don't know but expected ranges for throttle.  My neighbour's scan has 638 lines just for the engine on my wife's Mk3.

 

Good luck let us know how you get on.

 

Need to know which of these throttle mentions are relating to the pedal under your right foot, and which are the bit in the engine bay that helps regulate EGR flow rates and clean engine shutdown.

 

Seems to be some contradictory info early in the thread:

15 hours ago, AOwen said:

OBD2 scanner shows the throttle position as 88.6% constantly, even at idle and the throttle actuator at 95%, also constantly

This is the bit in the engine bay, is it, actual and commanded position??

 

15 hours ago, AOwen said:

Absolute pedal position varies from 12% at idle to 80% at full throttle

 

The latter of these suggests the pedal is probably behaving itself, I think?

 

 

I think it is pointing to an air leak in the air pressure pipes between the turbo/ intercooler & inlet manifold.

Look for any sign of black sprayed oil residue on any adjacent surface which will be ejected from any split or leak.

 

Also check the throttle valve on the inlet manifold.

 

They get covered in black sticky EGR crud & start to jam up, although your fault codes don't really support this.

 

If you remove it to clean, remove the plastic cover on the side as well.

It covers the electronics & drive motor.

I have found some to be completely full of black conductive engine oil in the past which of course shorts out the electronics.

Give all the electronics a good clean with something like brake cleaner including the electric motor.

 

 

11 hours ago, sepulchrave said:

Intake leak fault under deep manifold vacuum suggests a vacuum leak, don't just use your eyes, give those connections a good pull.

 

Ignore this, I missed that it was a TDI, since a TDI doesn't have a proper throttle then I'm not surprised that the reading shows it's open when the engine's running, it only closes when you switch the engine off.

 

So ignore that reading, it's a red herring and start looking for air leaks.

3 hours ago, sepulchrave said:

it only closes when you switch the engine off.

Not the case in EA189 and more recent diesels.

See Uwe's first post here: EGR/Throttle adaptation Skoda 2010 | Ross-Tech Forums

 

11 minutes ago, Wino said:

Not the case in EA189 and more recent diesels.

See Uwe's first post here: EGR/Throttle adaptation Skoda 2010 | Ross-Tech Forums

 

 

It still doesn't close until the engine's off, you're misunderstanding the amount of attenuation it does, the engine cannot physically run with it shut, it's an ASV when closed.

Because it's a TDI there shouldn't be any appreciable manifold vacuum under any conditions.

It will change angle as demanded while running (if working correctly).  You may have wished to mean "it only closes completely when/as the engine is switched off" but that's not what you said.

 

I never claimed it shuts completely during engine running.

I never claimed anything about manifold vac levels either.

 

Just trying to help the OP understand his car. 🙂

 

 

Edited 14 December, 20214 yr by Wino

6 hours ago, Wino said:

This is the bit in the engine bay, is it, actual and commanded position??

Yes, actual =88% and commanded = 95% all the time, load, idle, ign on but not running, never changes

Maybe needs a clean out as suggested by PipH.