VW Passat Tdi Sport 130 2002 - Loss of Power - Turbo not kicking in

**nuttley** · 14-02-2008,12:59 PM

Hi, i'm new to the forum, although i've used it before to sort the wonderful water in the footwell problem, thanks to everyone who contributes it must save lots of people a lot of cash!

Rather than starting a new thread on what seems to be a common turbo problem i thought i'd try here for a little more info. I have a 2001 130PD and the turbo is only coming in about 2.5k-3k rpm no black smoke or any other issue. I tried thrashing the knackers off it to see if it cleared anything but that just put it into limp mode, after hittting the red line a couple of times. So i figure it could well be the MAF or MAP sensor and want to try changing these first. I know where the MAF sensor is but could someone detail a little more where the MAP sensor is? I have this descption from another thread "MAP sensor is located on the boost pipe that runs across the back of the engine bay and is held in with two screws, either Phillips or Torx head" is it easy to get to or obvious to see? i dont know what i'm looking for and cant find a photo on here, if someone has the part numbers for these or where i should look for them it would be really appreciated.

**Crasher** · 14-02-2008,07:05 PM

I think you should have a fault code read done first.

**nuttley** · 14-02-2008,09:44 PM

Thanks for that, i think your probably right about the code, it makes sense judging byt the cost others have metnioned. Will be on to my local VW garage in the morning, cheers

**nuttley** · 18-02-2008,12:29 PM

So i had the fault codes read at my local independant garage and it was showing

17965 P1557
Turbo Sporadic:super charger overboost
condition:control limit exceeded.

The car was then taken for an 8 mile trip and re read with no fault codes coming back.

Am I right in assuming this is likely to be the MAP or the vanes sticking?

The garage said the possible causes were 1.Hose connection interchange/not connected 2.TC Boost pressure sensor 3. TC waste gate regulating valve

**Crasher** · 18-02-2008,02:39 PM

Usually sticking vanes but can be the MAP sensor. The explanations they gave you were the ones listed by VAG which don't take into account defects VAG didn't expect. If it was the MAP sensor (VAG call it a Thrust Sensor) it would more than likely have re-occurred very quickly on a road test but sticking vanes don't always register quickly.

**nuttley** · 18-02-2008,03:43 PM

thanks for the info. i went out and got a MAP sensor this lunch time given the cost is low and i cant get the car into the garage for a week. The garage told me they know of someone they use that has a machine for flushing turbos (i think that was how they said it) ever heard of these? know if they are worthwile and likely to clear sticky veins?

Going to change the MAP tonight and will post up if it makes any difference.

**Crasher** · 18-02-2008,04:55 PM

I have heard off it but not had experience of it.

**nuttley** · 19-02-2008,10:15 AM

well changing the MAP seems to have done the job. The turbo now kicks in as it should, although i'm not convinced its as powerful as it should be and after reading some of the mpg threads its not as good as it should be. I could see gunk in the pipe the MAP is attached to, is that normal? I guess its worth cleaning the pipes out either way. I noticed that where the pipe connects to the other pipe (excuse my poor descriptions) heading towards the front of the engine bay there was some oil, and it is clearly coming from around the join.

**Crasher** · 19-02-2008,04:56 PM

A little oil in the charge pressure pipes is normal.

**wizard786** · 05-03-2008,05:02 PM

Originally Posted by Crasher

The VW explanation for that code is; 17965/P1557 Charge pressure control, Control limit exceeded. Possible reasons, Hose connections interchanged or not attached. Effect, charger pressure too high so reduced output. Check N75, check charge pressure control.

I have seen this many times on this model due to the Manifold Absolute Pressure (MAP) sensor sticking at an indicated 2880 mbar. This sensor is located on the boost pipe that runs across the back of the engine bay and is held in with two screws, either Phillips or Torx head. The sensor is available from VW under the part number 038 906 051 C and costs £34.72 inc. VAT from VW and takes minutes to fit. This part number is for a 2002 Passat with either an AVF or AWX engine. If the turbo vanes jam, they tend to have the same effect so really you need someone who knows how to use VAG-COM and Basic setting 04, sub group 011 to trigger the vane control actuator and measuring blocks 08, sub group 011 to observe the actual boost pressure in display zone 3. Using Basic settings 04, 011 it is often possible to free off jammed turbo vanes without resorting to removing the turbo.

hi crasher i have a power loss problem and have vag com was wondering if you could be a bit more clear on section you have to go to to look at readings am pretty sure its either my map sensor or N75 but i dont want to waste money on guessing if you want to mail me direct you can on shazad.manzoor@orange.net as i cant always get on tyre smoke.