Just got in after a motorway drive of about 15 miles. Traffic was medium to heavy so it was slow down then accelerate to speed most of the way.

After about 6 miles I went to accelerate and was getting no more than 5 psi of boost. Flicked the Liquid to fault read and got 17536 code Cleared it on the go and full boost was restored without needing to stop and restart engine

Just checked the code and comes up with the following:

17536 - Long Term Fuel Trim - System too Lean (Bank 1)

or Fuel Trim: Bank 1 (Mult): System too Lean : P1128

I refitted my CAI yesterday and I'm wondering if this has something to do with it as I have never had this happen before :confused:

Opinions please.

Ian

Possibly one of the breather hoses underneath the inlet manifold has split. Mine gave similar fault codes when I had a split pipe.

I have just replaced 3 of these breather pipes, bringing up this fault code. Pull all the plastic covers off and with the engine running have a look (and a listen)

A quick search looks like vacuum pipes but an outside chance of the Maf.

Edited 18 February, 200917 yr by martziniuk

Cheers guys will check the pipework tomorrow, will also remove the CAI and see if code returns. Seems coincidental that I put it on and get this problem. I know the Y shaped breather pipe is fine as I check it whenever I go under the bonnet as this one is prone to splitting apparently.

Will update once checked.

Ian

OK having done some searches it would seam that a split vacuum pipe would cause 17544 rather than 17536.

Got this from Ross tech:

17536/P1128/004392 - Fuel Trim; Bank 1 (Mult): System too Lean

Possible Symptoms

• Malfunction Indicator Light (MIL) active
  

Possible Causes

• Mass Air Flow (MAF) Sensor faulty
  
• Oxygen Sensor Control faulty
  
  • Oxygen Sensor(s) faulty
    

  [*]Fuel Injector(s) faulty

Possible Solutions

• Check Mass Air Flow (MAF) Sensor
  
• Check Oxygen Sensor Control
  
  • Check Oxygen Sensor(s)
    

  [*]Check Fuel Injector(s)

Anyway I am still airing towards the CAI as this is the first time I have had it on since the remap and I get a problem within 24 hours so have replaced the standard box & PiperX panel for the time being to see what happens. Took it for a long drive since driving similar to when the fault occured and no limp mode or codes so far.

One thing that is curious is that with the CAI removed and the factory box back on the air intake temperatures are about 10 centigrade lower.

So much for cooler denser air with a CAI :confused:

Will update as necessary

Cheers for your help with this.

Ian

That's because the standard airbox is frikkin awesome!!

Maybe you nocked the MAF while you were putting the drainpipe on?

My money is on it being a breather hose though. When I bought my car I think I had the same code (can't remember it exactly but it was a lean one), a garage changed the two hoses highlighted below for me, and it's been fine since.

I'm surprised Samco or Forge haven't made silicone versions by now.

My fault code was 17544/P1136/004406 - Fuel Trim: Bank 1 (Add): System too Lean. Which according to Ross Tech the "Add" bit means Additive and the lean mixture is at idle. Where your fault code is "Mult" which is Multiplicative and indicates a fault at higher RPM. So more likely the MAF.

Heres the link anyway Ross-Tech: VAG-COM: Fuel Trim Info

After a bit of hunting....

Eurojet make a PCV repair kit if you need one. But their American.

Eurojet 1.8T PCV Hose Replacement Kit

Off topic- I LOVE their 'grenade' DV!!

Give it a run and log the maf values, Should be around 150g/s (standard) 170g/s+ (if mapped)

HTH

OK thank you everyone you have been a great help.

I'm leaning towards the MAF, I have all the reciepts from when the car was new and there is no evidence that it has ever been changed so 107k isn't bad for it's lifetime.

If it repeats itself I will replace it. May replace it anyway as it's not hard to do.

Going to stick with the stock airbox.

I'm sure better quality CAI's do their job and do it well but I'm not investing in another one after seeing the air temperature difference at the manifold. That was a big surprise :eek:

Bodge that grenade DV is cool

And finally Fatty just noticed your post, you posted as I was typing this one thanks for that that is very helpful will check it out later today

Ian

I think the CAI vs Airbox fight was put to rest a few years back by Eddy H

Iirc he did some RR's with a both items and the airbox came out the winner in the power stakes. But if noise is your thing then the CAI is FTW.

Code and limp came on again today again during several miles of motorway cruising. Am going to replace the MAF and hopefully that will end it :(

Ian

Code and limp came on again today again during several miles of motorway cruising. Am going to replace the MAF and hopefully that will end it :(

Ian

Have you tried logging the MAF values.

As this will tell you for sure if it's a borked MAF.

hello mate if its the maf then you will get some mad figures from the lg look at the figures as above. sounds more like a split pipe mate tbo

how many fault codes are you logging on the lg?? as it only stores 4 codes so there might be more...!!!

bro inlaw has vag com mate if you need me to pop over mate i will

OK gave it a burst to redline in 2nd today and logged a max of 176g/s Have also checked the hoses and they seem OK.

I only get the code and limp mode during sustained motorway driving. Have ragged it around town and nothing but hit the duals or M/ways and after 10 Min's or so at constant 3 - 4k rpm and suddenly low boost and the DTC.

I did knock the MAF when I moved it to 1 side when fitting the CAI so maybe it did some damage and the MAF is failing as a result. Also the pipercross cone on the CAI was oiled but I don't know if this has any bearing on it.

Also been keeping an eye on A/F ratio and it has been fine every time I look but obviously I can't watch it continuously over an hours driving.

Noticed on the run to Oxford today that mpg was about 4 mpg down on usual as well.

Ian

THat figure sounds normal.

Unless it's intermittantly playing up, although I'm not sure if MAF's do this or if they just read lower constantly if that makes sense !!!

Cheers Fatty, this is doing my head in Ordered a MAF from VW and it will be here on Saturday so will change it anyway. Like I say it's done 108k now so it's had a good innings. If that doesn't cure it I'll let an indi look at it :(

Ian

Does it sound not quite right on idle, if you have the bonet up?

You should be able to see the green hose I highlighted above, connected to the centre underside of the inlet manifold, if you remove the 2 plastic engine covers. While the engine is running, carefully get your hand under the manifold (from above) and give that hose a poke, to see if you can hear any funny sucking noises or changes in engine note when you disturb it.

It's a quick and easy check if you haven't done it already. It's like a birds nest under there! I'd love to just rip it all out and start from scratch one day.

Idle is fine, there are no obvious symptoms until limp mode hits then a code scan shows the DTC. Car runs fine and you don't even notice it's switched to limp mode until you floor it and think "where's my power?"

Ian

Idle is fine, there are no obvious symptoms until limp mode hits then a code scan shows the DTC. Car runs fine and you don't even notice it's switched to limp mode until you floor it and think "where's my power?"

Ian

Yeah I know what you mean there! Mine occasionally goes into limp when the TB gets really dirty, and you don't notice until you gun it!

Had it a couple of months back, and didn't realise till I needed the power on the motorway to pull away hard from someone! Looked down at the boost gauge to see I was only boosting to 5psi. Annoying.

Fingers crossed for the MAF fixing it mate :bowdown:

Cheers bud, just had another prod around and no change in engine tone. That L shaped pipe in your pic is directly behind the dipstick? Thats the one I concentrated on although I moved anything I could see that was connected to the manifold.

Throttle body clean might be an idea. Think I will try it as well. Carb cleaner and cotton bud jobbie isn't it. My TB was new at 81k but hasn't been cleaned since so would be worth it.

Will phone Skoda now and see if they have a gasket in stock.

Ian

I've had a thought on this so I'll see if it makes sense.

When I got the LG I performed a throttle body reset.

Now assuming the TB is gunked up could it be possible it didn't close fully during the calibration and the new values have been stored with a partially open TB.

During motorway driving quite often you get someone slower move into your lane and you lift off or simply reduce throttle for 5 - 10 seconds or so.

If the TB was partially open but the ECU thinks it's fully closed it would be getting more air than it is expecting causing it to run lean for a few moments.

Does that sound plausible, I'm racking my brains for idea's and solutions and this thought entered my head. I may be wide of the mark but I think it might be possible.

Ian

Update:

Changed the MAF yesterday.

During the first couple of drives it had developed a part throttle stutter/hesitation however this has now disappeared and it is running smooth again under any throttle load.

I can only guess it needed to adapt to the air values.

Average MPG has improved by 2-3 MPG.

Have done a motorway blast to see if limp or the code reappear and so far so good

Got everything I need to clean the TB so am going to have a go at this this week and will be venting the CCV to atmosphere under the car and plug the necessary inlet port to limit any future build up of gunk.

Whilst I'm under the car I have had an idea on securely fitting the undertray so will be doing a guide on that when it's done. It's been off the car for a couple of weeks now and I really want it refitting.

Thanks for all the input you have been really helpful. Virtual beers all round :cheers:

Ian

Took my superb to a local Skoda dealer with same problem on the diagnosis machine. They replaced I think it is called the lander sensor on the exhaust system on the cat. The engine management light came on again after 5 miles, took it back put it on diagnosis machine this time they told me it was the ecu that needed replacing at a cost of £600. I decided to get an independant garage to look at it they found that a vacuum pipe from the manifold had split. They taped it up till i got the new part. The management light didn't come back on. I got the new vacuum pipe fitted at a cost of £6.52 and still the light hasn't come back on. Got an apology from the Skoda dealer plus my money back and a free service after arguing that they wasted a lot of my time and was going to fleece me out of £600 when I didn't need an ecu. The moral of this story is get proper mechanics to look at your car and don't assume the dealers are the best people to deal with your car.