Hi, i had engine light come on and so went to garage and had fault codes read. Car is fine from start up until reach 67-68 mph then lose all power. power is not regained until have switch engine off and then on again. power loss is everytime hit that mph, if keep under that mph from startup the car has all the power available all of the time. Car is a 2004 audi a4 1.9tdi. this is the one which the seperate grilles not the big one piece grille of the later cars.
Hope someone can point me in the right direction.
P0243 Turbo wastegate solenoid (A)
P0401 Exhaust gas recirculation flow insufficient detected
P0299 Turbo under boost
update.
I went out in car earlier and it was fine on way there but on way back about 50 mph went into low power condition thingy.
It feels like no turbo. Turbo definanately working before fault thingy. Turbo no go??? after fault thingy has happened. feels like n/a engine
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puggered
The car is going into limp-home mode to protect the engine.
Those are odd codes for one of these; didn't the garage have the ability to access the, much more informative, VAG-specific codes?
This could be sticking turbo vanes; but I'd be very cautious in taking precipitate action based on just those codes. System checks on the N75 vacuum turbo-control solenoid and it's hoses are a good place to start.
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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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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.
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i have removed the pipe from the egr valve and plugged the pipe and this has cured the problem. is there any problems etc with doing this?
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Yes; because that wasn't really one of your flagged problems? You've just masked the symptom; you haven't fixed anything.
Address and solve the actual faults one-by-one; or this may come back and bite you.
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sorry that was wrong, i plugged the egr valve and it has made no difference what so ever so i have reconnected it again. i have removed the egr valve and found it to be dirty, the flap moves fine. how hard should it be to move the plunger rod thing that the vacuum part of the egr attaches to?
i have a diagram but dont know how to upload it
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i have a diagram but dont know how to upload it
Host it on somewhere like www.imageshack.us and then post the link to it here.
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if you look at this pic from ebay. it is closest to the bottom where like a metal air?? pipe connects on to it whilst on the car. this plunger at this end is really stiff to move.
cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item...7
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Can't say how much effort is required as I use a vacuum pump to move 'em; there's quite a spring behind it; but it shouldn't be stiff and jerky.
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to put the effort require to move it in perceptive. its on par with placing a new suspension shock on the floor and trying to compress it. ie you have to give it a good force to move it.
very similar force to that of a cars thermostat
Edited by puggered on 05/06/2008 at 21:36
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That's not excessive; there's around 30lb of force available to retract it.
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On VAG PD engines you can carry out a functional check of the vacuum actuators for the EGR and VNT by mouth suction.
Use a length of suitably sized tubing (they're different sizes) and suck hard. You will "feel" the EGR valve open and by maintaining the vacuum by putting your tongue over the ebd of the pipe you can test the integrity of the diaphragm. When you "let go" you should hear the EGR valve close with a soft click.
The VNT is tested in a similar way, but put your fingers under the actuator and feel the pushrod whilst you do the test. It should move about 20mm with a good hard suck. It does not "click" on release, but watch the end of the rod and check it moves back smoothly.
I exercise these things a few times at each service. A sparse smear of silicone grease on the stubs stops the hoses from sticking.
659.
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fault now is very frequent from start within a couple of minutes its in limp home mode. Defo can confirm car isn't boosting at all during limp home. but is boosting fine before car goes in limp home.
What is vnt? is it the turbo vacuum thing (dump valve??), the thing that looks identical to the vacuum thing on egr?
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Sorry, I should explain abbrevations when I use them. VNT is Garrett speak for variable nozzle turbocharger ie one in which provision is made to adjust the degree of boost by varying the angle of the "fixed" vanes in the turbine. It's a far better bet than a wastegate and allows useful boost to be developed at lower engine speeds. It also gives lower exhaust back pressure when low levels of boost are required, greatly aiding engine efficiency at part load.
The VNT actuator is the vacuum operated actuator which moves the control rod for the turbine vanes. It's circular and looks a bit like the wastegate actuator although is not so shiny and has a narrow bore flexible vac pipe attached to it made from VAG's best rot prone rubber - first seen on the air cooled beetle.
659.
Edited by 659FBE on 06/06/2008 at 22:57
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when i take off pipe that connects to vnt actuator and put a pipe on it so can suck on pipe, i cant get it to move no matter how hard i suck, however if i stuck on pipe and put my fingers on the rod thing underneath it, i can just about get the rod to move, max movement is 1 cm only a guess though.
What would happen if i disconnect the pipe on the vnt (proper one fitted to car) and run/ drive car?
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You're probably getting close to finding the problem which may be sticking VNT vanes. It needs a hard suck, but on my AWX engine I can move the actuator rod a full 20mm by mouth. If you run the car with the pipe disconnected you will get a vac leak, no boost and a fault code due to required boost not being achieved.
I would attempt to exercise your VNT actuator possibly with a little penetrating oil at the point where the rod crank enters the back of the turbine housing. This is a long shot as they usually coke up internally but it's worth a go. VNTs are well worth re-building to free the vanes as the rest of the turbocharger gives little trouble. Getting it off the engine is fun - don't break the oil pipes.
659.
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what about if the pipe is blocked up as like you can do to egr
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Then you get all of the above except for the vac leak.
If your VNT has failed the "suck" test, I suggest you take a good look at it.
659.
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i would have thought though that by disconnecting vac pipe, this would stop the vanes adjusting themselves and so the turbo would act as if it was a fixed vane turbo, and so it would create boost at a certain rev range, ie wherever the vanes are placed the boost area would be, and so if moved rod that moves the vanes, different boost ranges could be achieved.
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One of the less often discussed advantages of a VNT turbocharger as opposed to a standard unit with a waste gate (aptly named) is that there is less exhaust backpressure when boost is not required. This gives a greater engine efficiency when the engine is working at light load.
On the VAG installations, no vac = very little boost. If they had designed it any other way the engine could be at risk if the pipe fell off.
659.
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This link might help explain the VNT and its little ways: www.technologie-entwicklung.de/Gasturbines/VNT15-T...l
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so how hard is it to remove turbo?? what tools will i need? what should i use to clean vanes etc?
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update:
Vehicle failed suck test on vnt operation and turbo has been stripped to clean the vanes which was clogged solid.
Problem now cured.
Many thanks to all who helped in the process in order to locate/ fix problem.
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hi just been reading threw the pages i have a audi a3 1.9 tdi 105 bhp with a fault code of po299 it has had every thing done to it eg exchange turbo, air flow meter,egr valve the fault will clear but after driven for a while lack of power. Just sending you a email because you said dont fit a exchange turbo any ideas thanks again andy.
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Andy
That's an odd code for a VAG car. What was reading it and why isn't there a VAG 5-digit code to go with it? Is yours a BKC engine?
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hi it is a 2004 not to sure about the bkc engine ill take the audi to main dealer and get the fault code and 5 digit number on friday thanks
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hi had the fault code read today buy my local audi dealer here is the code (16683 charge pressure control value below control limit ) i also replaced the n75 valve ( turbo modulator) driven the car on a motor way today only faults when it gets to 75 mph plus then you turn engine off and drive again and will go above 80 mph.
any ideas
it is a bkc engine
Thanks again 981andy
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Andy
The dealer's definition of that code would suggest underboost. Check for any leak in the intercooler and the ducting.
A coked turbo would be a very likely cause; but an under-performing MAP sensor is one of several other possibilities.
What year is this A4 and what's the mileage?
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hi it an Audi a3 2004 done 95000 had a new map senor and a exchange turbo at 90000 il check Intercooler and hose but no noises from the car while driven (eg whooshing or smoke)
thanks 981andy
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Andy
Sorry; just realized that you had already given me the year etc. [I hate tack-ons.]
So both codes agree - low boost. Do check for leaks and splits - usually only betrayed by oil mist.
If that doesn't work - and most things have already been tried - then it's duff new parts or maybe an exhaust restriction?
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just had the eml light come on again, fault code read '19586 egr system control range exceeded p3130 intermittent'
Anyone help me fix this problem.
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In view of your low boost; check that the EGR valve isn't stuck open.
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