Recently I've been having a problem with my Sharan. This began with a brief judder whilst in 4th doing 30, the fault light then soon flashed and as the problem didn't reappear the light stopped flashing after a day or so. A few weeks later the same thing happened and reappeared every few weeks or so. As it was due a service I had the guys run a diagnostic check but they could find no problem. The problem now is more serious in that the judder seems to have been replaced by loss of power. This can happen on a motorway or anywhere and usually occurs climbing a hill, regardless of gear. Yesterday I drove on the M3 and whilst climbing a gradual incline power appeared to just drop away (the engine does not die though) and the car slowed to around 30mph forcing me off onto the hard shoulder. This problem resurfaced time and again on my way home. By chance I realised that if I turned off the engine and then restarted all was well, at least for a short time anyway. So I'm wondering if this could be some kind of sensor problem that disappears upon turnoff/restart when the sensor is reset.
Can anyone help with an idea of what the problem maybe and what approximate cost I'm looking at for fixing? Any help most appreciated.
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I see you have been living with this, on and off, since December last year! My uninformed guess would be the Mass Air-flow sensor, having just had a similar problem on a GM diesel engine; the power loss was nothing like as bad as yours and the car ran with the ENG light on for about 18 months!
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I am assuning that this is a VW PD engine ?
You are experiencing "limp mode" where the ECU limits engine power.
If a CEL was lit in the past then there will have been a code logged and there are probably codes logged now each time it "limps".
Can you find out what they are and post here ?
I would guess that there is an overboost condition caused by jamming of the VNT turbo vanes or a sensor, MAF or Coolant temp ot MAP have been implicated in the past.
I was going search TDIClub and relevant links but it's down at present; so I suggest you go to forums.tdiclub.com/ and search for "limp" and see what you get.
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"Iwas going search TDIClub and relevant links but it's down at present; so I suggest you go to forums.tdiclub.com/ and search for "limp" and see what you get."
It's back. Have a read :
forums.tdiclub.com/showthread.php?t=135244&highlig...p
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seezed
You need to get the codes read before spending-out on parts as there should be, at least, one now stored. It sounds as though it's defaulting into "limp-home" mode when the ECU is detecting a serious problem. The circumstances of it's occurrence suggest the common code 17965 "Turbo over-pressure condition" could be the most likely.
That one indicates turbo "wastegate" operation failure on the VNT turbo. It's often the turbo coking-up; but it can also be flagged by problems with the turbo control solenoid or the vacuum control/boost pressure detection systems.
Do you know your [three-letter?] engine code?
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Previous problem seemed to have disappeared for a while - how wrong I was.
How do I check/look for "fault codes"?
Engine code is AFN.
Thanks
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seezed
Isn't code-reading what your garage meant by "running a diagnostic?" Most garages can get code-reading done these days. If you want to read them yourself, the socket's under the ash-tray and you could try a lap-top programme like Vag-Com or one of those Chinese DIY code-readers on e-bay; [best of luck!]
AFN engines have a specific fault with the manifold pressure sensor which is remotely mounted inside the ECU. It's hose from the inlet manifold can deteriorate or block-up. Worth a quick check before digging deeper.
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Sorry screwloose - if the garage run a "diagnostic" and can't find a fault not much I can do about that really. Will have a look at a diy diag programme myself though not sure what I can find out that a garage can't.
As for the latter part will certainly look into that. Thanks
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forums.tdiclub.com/showthread.php?t=75959
Have a good read through the above link, may be of help.
Make a large coffee first!
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