Morning All

For the second or third time now I've had the car enter limp mode which accelerating up a hill. I did do a VAG-COM after the first time, but that was the first time I had read the car so I just cleared the codes. Since then I haven't had the time to read it again.

I'll probably not get a chance to read it until the weekend, but I'm guessing this is most likely to be a vac hose problem, but how do you go about finding which one?

Tom

110 TDI + limp + booting it up a hill = probably sticky vanes in the turbo.

Do you feel the power starting to back off around 3500-4000rpm and then limp occurs?

Remove the vacuum pipe from the n75 valve to the actuator arm on the turbo, and when the engine is cold put your hand/fingers down on the actuator and then suck on the end of the vacuum hose. You should get a nice smooth action when applying the vacuum or when you release the vacuum it should return smoothly.

If you think you have a vacuum leak, run the engine for a minute or to, and then stop it, open the bonnet and wiggle the rigid pipe work which comes out of the vacuum pump. One of the joints on this was split on mine.

Just incase you start playing with your pipes and get confused as to where they all go, I have marked up an couple of images here.

I don't think the power backs off, but between 3-4000 revs and I think as I change gear it just collapses to non turbo'd mode.

I'll get the VAG-COM out and check the codes, and have a look at the actuator. Without appearing like a complete wally, which is the n75 valve?

Tom

Edited 5 April, 201115 yr by tomsimmons

I don't think the power backs off, but between 3-4000 revs and I think as I change gear it just collapses to non turbo'd mode.

I'll get the VAG-COM out and check the codes, and have a look at the actuator. Without appearing like a complete wally, which is the n75 valve?

Mine sometimes would feel like it was running out of power, and other times felt fine till I changed gear (a bit like what you are experiencing).

n75 location:

Actually seeing the actuator is quite hard, but if you have slim arms you can slide one down near to the EGR/anti-shudder assembly and get your fingers onto it. It might be a little trial and error to start with, but if you are sucking on the vacuum pipe from the n75 (the lower one on the left side of it) you should feel something moving.....(obviously do this when it is cold, otherwise you might burn something!)

Edited 5 April, 201115 yr by mbames

Thanks for your help here.

I'm afraid I don't fit into the "slim arms" category.

Which pipe do I take off and suck on, the oe from the right that curls round and down or the one from the top that has the T piece in?

I'm guessing you can't feel something just from the suck, ie suck harder and harder then it should start to move until it reaches full travel and then your head will implode if you don't stop sucking?

Tom

Which pipe do I take off and suck on, the oe from the right that curls round and down or the one from the top that has the T piece in?

When viewed as in my picture, it is the lower of two pipes to exit on the left hand side. It should not have a T piece in it (that is the upper pipe. The pipe in question, you should be be able to follow across the bulkhead for a bit and then it is clipped onto the air pipe which runs down to the turbo.

I'm guessing you can't feel something just from the suck, ie suck harder and harder then it should start to move until it reaches full travel and then your head will implode if you don't stop sucking?

I can;t really tell when you suck how well/smoothly it is moving. If you hear some creaking then it might well be semi-seized (either vanes, or rust on the control rings). If you can make your head implode you are doing better than me.

If you want you can crawl under the car, remove the engine tray and get it from there.... but that involves more work.

Finally had the time to dig out the Vag Com and check the codes.

I'm getting...

17965 - Charge Pressure Control: Positive Deviation

P1557 - 35-10 - - - Intermittent

I'll be doing some work on the carthis weekend, finally finishing the brakes, so I'll try and check the turbo movement.

One thing, you say access the actuator from beside the EGR, that's the big section on the back left that the intercooler return goes to isn't it? How pray tell did you get your arm down there, while sucking on the pipe from the N75 over on the right? Or is there sufficient pipe to reach across to the left?

Tom

I managed it and I'm 17 stone and six foot 1. Not really slim arms then...

Awkward to get to though. The actuator is located somewhere down the back of the crankcase - offside centre. Follow the vacuum line down from the N75 and it leads around to the bottom of the actuator. The moving arm and lever are on top of it. Getting at it is easier with the engine cover off. I found I could just about see the actuator / lever arm moving from the top with the cover off and leaning over the bonnett. You can sort of see the bottom of it looking down from the nearside past all the pipework but not much of the actuator or arm.

With 17965, I'm pretty certain that you'll have a stuck actuator or vane mechanism. I use a generic code reader and got 17598 but think that's my problem. Apparrently the generic reader might be misreading it and with VAG-COM I might get the same as you. Confirmed stiff and creaky movement of the vanes / actuator anyway - particularly towards the low vacuum position.

May get my turbo removed and cleaned in conjunction with upcoming service, depending on whether the mechanic agrees with my diagnosis.

Edited 27 May, 201115 yr by Uriel

Finally had the time to dig out the Vag Com and check the codes.

I'm getting...

17965 - Charge Pressure Control: Positive Deviation

P1557 - 35-10 - - - Intermittent

I get this fault on mine, but I am sure my turbo is fine. I think either my n75 or one-way valve is at fault. I am yet to figure out which though (not replaced anything), but I had my turbo off and cleaned it, so I think that is ruled out of the problem list.

I did replace all my vacuum pipes as they had seen better days. I was talking to a Skoda dealer the other day about this, and they just said "we place parts: turbo first, MAF, n75 and keep going till it fixes it". Basically you sign a big cheque and let them try and fix it. What made it even worse was the broke said his car had this problem, and he had not had it fixed, and he worked at the dealers. Needless to say that Skoda won't be fixing this problem on my car, as I am not prepared to let them fit new bits and charge me for all of them till it works. As they carry nothing in stock, it all has to be ordered in, and thus the customer pays. Cr@p Skoda Customer Care if you ask me