error code

[turbo1121]

VCDS-Lite Version: Release 1.2
Sunday, 31 May 2015, 15:33:26.
Control Module Part Number: 038 906 019 LR
  Component and/or Version: 1,9l R4 EDC G001SG  1565
           Software Coding: 00002
            Work Shop Code: WSC 00020
                      VCID: 729759CB2DB7
1 Fault Found:
17964 -  Charge Pressure Control: Negative Deviation
        P1556 - 35-00 -

If any one could suggest a starting point or the most common cause the car seems to lack power but then it comes back doing my head in.

thanks in advance

[Mirez]

Negative deviation means the car is expecting more boost then its getting from the turbo, although worst case could be turbo failure its FAR more likely this is caused by a leak in the pipework. You should amend you signature/profile details to tell us what variant of the diesel you have as the pipework is different between the 115 and the 130/150 however I've seen both the L shaped pipe at the turbo exit and the S pipe at the bottom of the downpipe have holes in them which have caused this...

[turbo1121]

thanks for the reply it is the 115 model

[Mirez]

In that case I would start with the S pipe that joins the downpipe from the turbo to the intercooler. You'll need to remove the undershield and then you'll find a large aluminium pipe clamped to the drivers side of the engine coming from the turbo, the pipe from there into the intercooler.

[turbo1121]

thank for the reply I will have a look at that today and let you know how I get on.

thanks again

[insanitybeard]

Could the negative deviation fault code not also be caused by sticking turbo vanes or defective vacuum control?

[Chrispb]

In reality it could be any of those things, work through the easiest items first.

[turbo1121]

Checked the pipework and all seems fine no leeks or anything..

defective vacuum control is that the n75 valve/switch

thanks again guys.

[Chrispb]

Yes the vacuum supplied to the turbo actuator is controlled by the N75 valve

[turbo1121]

changed n75 and vacuum hoses and car still same seems to be in limp mode all the time (wont reset after turning engine off).
also had turbo off it was fairly coked up cleaned it out now moves free no sticking

just had it round block with laptop attached these are the results from block 11

038 906 019 LR    1.9l R4 EDC G001SG  1565    
               
   Group A:    '011          
      Engine speed    Spec. intake press.    Actual intake press.    D.cycle MAP
   TIME    2850-3150    2000-2150    2000-2200    40-95%
Marker    STAMP     /min     mbar     mbar     %
   0.69    903    979.2    805.8    19.9
   1.41    1050    1040.4    795.6    19.9
   2.13    1008    1009.8    795.6    21.9
   2.83    1428    1009.8    785.4    58.6
   3.55   1449   1009.8   785.4    58.6
   4.27    1449   1009.8   785.4   58.6
   4.97   1428   989.4   785.4   58.6
   5.69   987   979.2   805.8   26.7
   6.4   903   979.2   805.8   19.9
   7.12   903   979.2   805.8   19.9
   7.82   903   979.2   805.8   19.9
   8.55   903   979.2   805.8   19.9
   9.26   903   979.2   805.8   19.9
   9.98   903   979.2   805.8   19.9
   10.69   1050   1122   795.6   19.9
   11.41   1008   1193.4   805.8   19.9
   12.12   1092   1387.2   816   19.9
   12.84   1638   2111.4   795.6   19.9
   13.55   2121   2244   816   19.9
   14.27   2667   2182.8   836.4   19.9
   14.97   2562   989.4   836.4   38.6
   15.69   1617   1040.4   816   57.8
   16.41   1785   1275   826.2   19.9
   17.13   1827   1020   805.8   49.8
   17.85   1869   1152.6   795.6   41.4
   18.57   2016   1907.4   816   19.9
   19.29   2163   2172.6   846.6   19.9
   20.01   2352   2172.6   867   19.9
   20.73   2037   969   846.6   38.6
   21.45   1554   1142.4   805.8   43
   22.17   1512   1570.8   816   19.9
   22.88   1428   969   795.6   58.6
   23.61   1302   969   795.6   58.6
   24.32   924   979.2   805.8   19.9
   25.04   903   979.2   805.8   19.9
   25.77   1134   969   795.6   58.6
   26.48   1050   1458.6   805.8   19.9
   27.19   1155   1591.2   816   19.9
   27.91   1239   1632   816   19.9
   28.62   1029   979.2   816   29.5
   29.35   882   979.2   805.8   19.9
   30.05   903   979.2   805.8   19.9
   30.77   1176   1570.8   805.8   19.9
   31.48   1281   1683   805.8   19.9
   32.21   1407   1846.2   805.8   19.9
   32.91   1554   1999.2   816   19.9
   33.62   1680   2091   816   19.9
   34.33   1827   2142   836.4   19.9
   35.05   1995   1825.8   846.6   19.9
   35.77   2079   1009.8   836.4   40.2
   36.47   1995   969   795.6   38.6
   37.18   1890   969   795.6   41.4
   37.91   1848   1642.2   785.4   19.9
   38.62   1911   2080.8   826.2   19.9
   39.35   2100   1989   846.6   19.9
   40.05   2184   1091.4   846.6   43.4
   40.77   2184   969   805.8   39.4
   41.49   2058   969   795.6   38.6
   42.2   1953   1122   795.6   41.8
   42.91   2100   1866.6   816   19.9
   43.62   2247   2182.8   846.6   19.9
   44.35    1995    969    846.6    38.6
   45.07    1470    1611.6    805.8    19.9
   45.78    1344    969    816    58.6
   46.5    924    979.2    816    19.9
   47.22    903    979.2    805.8    19.9
   47.92    903   979.2   805.8   19.9
   48.62   903   979.2   805.8   19.9
   49.34   903   979.2   805.8   19.9
   50.06   1155   1009.8   795.6   49.8
   50.78   1281   1672.8   805.8   19.9
   51.5   1470   1917.6   805.8   19.9
   52.22   1701   2040   816   19.9
   52.94   1932   1621.8   826.2   19.9
   53.67   1953   969   816   39
   54.38   1953   969   795.6   38.6
   55.1   1659   969    795.6   57.8
   55.82   1617   969    785.4    58.2
   56.55    1575    1091.4    785.4    44.6
   57.26    1659    1101.6    795.6    41.8
   57.98    1722    999.6    785.4    58.6
   58.71    1638    1244.4    795.6    37.5
   59.42    1890    1764.6    816    19.9
   60.12    2058    1754.4    836.4    19.9
   60.86    2247    1744.2    856.8    19.9
   61.58    2016    969    846.6    38.6
   62.28    1449    969    816    58.6
   62.98    1386    1315.8    795.6    19.9
   63.7    1491    1785    805.8    19.9
   64.42    1533    1132.2    816    19.9
   65.14    1512    969    795.6    58.6
   65.86    1218    969    795.6    58.6
   66.58    924    979.2    805.8    19.9
   67.3    903    979.2    805.8    19.9
   68.02    903    979.2    805.8    19.9
   68.74    903    979.2    805.8    19.9
   69.46    903    979.2    805.8    19.9
   70.18    903    979.2    795.6    19.9
   70.9    903    979.2    805.8    19.9
   71.62    903    979.2    805.8    19.9
   72.34    903    979.2    805.8    19.9
   73.06    903    979.2    805.8    19.9
        73.79       903    979.2    805.8    19.9
   74.5    903    979.2    805.8    19.9
   75.23    903    979.2    795.6    19.9

[Chrispb]

Looking at your figures you have no boost whatsoever, you say you've checked the pipework and is OK.
Visually have you looked/watched the turbo actuator when you start the engine, it should move from the minimum to maximum boost position.
If there is no movement remove the vacuum pipe from the turbo actuator and check for vacuum while engine is idling, there is also a joint in this pipe behind the air filter you can test from here without getting under car, see pic below.

[attachimg=1]

The feed to the N75 valve is from a T piece on the large brake servo pipe just behind the fuel filter, there is also a connector that's blanked off with a cap check this is not missing.

The red arrow shows the feed to the N75 the green arrow shows what should be a blanking cap, although the photo shows a clear tube connected.

[attachimg=2]

[turbo1121]

thank you for reply

i will check that in morning but a bit of further info is my mate has the same car and his works great we noticed a difference in when i squeeze the little L shape pipe from the egr on mine it stays squeezed in when engine is revved on my mates it pressurises the pipe and returns to its coorect shape.

[turbo1121]

and your right no boost at all car doesn't reset to give boost either..

[Mirez]

Well that would indicate you are missing the vacuum... Worth checking the reservoir is in good shape, it's the large ball shaped item at the front of the engine. I had a sharan once which had no boost and the pipe from the reservoir had sheared off as it leaves.

[turbo1121]

solved thank you to all that helped me out it was the turbo actuator that wasn't holding its pressure.

[Chrispb]

 

[turbo1121]

will it ever end

I have power now but its now got a positive boost deviation (overboost) I did make the vnt rod the same length as my old one only goes into limp mode at 60-70mph am I right in thinking I need to adjust the vnt rod??

regards as always John

[Chrispb]

Hopefully
You may need to do some more live data to see how bad it is.

Do blocks 003, 010, & 011

Make sure when your driving you get a good few seconds flat out (100% throttle) at around 3000 RPM

[turbo1121]

Thank for the reply I shall do that tomorrow as my laptop is being a pain doing updates..

regards
John

[turbo1121]

what is the best way to post the results ??

[turbo1121]

here they are thanks

[redbull2k]

[attachimg=1]
this is for better reading block 11.

Ideally like chris said you need some tidy logs 3rd gear foot down from about 2500rpm to 4000rpm. find yourself some clear road.

[Chrispb]

you have done block 005 instead of 010 so can't see whether you have 100% throttle in the 2800 to 3200 rev range or map and Maf value's
003 is showing EGR is closed when idling should be showing close to 60% or has your EGR been blanked off or disconnected.
Block 005 is showing engine temp of 60deg was the engine fully warmed up when you done test.
The boost actual reaches maximum several times that is not good.

Can you re do the log to show 003 010 011 and make sure the engine is up to temperature 90 deg

[turbo1121]

sorry did the wrong ones engine was still warming up as well i will re do it today and get back you you

thanks again

[turbo1121]

there we are and egr isn't blanked off and is clean.

[redbull2k]

[attachimg=1]

vnt rod needs to be longer to bring duty cycle down
i would expect to see <=80% at 4000rpm. If it doesnt get sorted quickly you could damage if not already your turbo.

[turbo1121]

ok thank you for the reply

[redbull2k]

make the rod longer by about 4 full turns.

[Chrispb]

MAF and MAP looks OK although EGR readings suggest diaphragm probably leaking although this wont cause your over boost.

You can only experiment with the actuator adjustment to get it back within the limits, as Redbull has already said lengthening the rod will reduce the boost.

[redbull2k]

has your car been remapped?

[turbo1121]

hi sorry for late reply have lengthened the rod and it no longer puts me in limp mode.
its not been remapped at least i think it hasn't

A little concerned about the  EGR comment what do i due to remedy this or is a new egr valve?

Regards
John

[Chrispb]

Have you done a log file since to compare?
You cannot repair the EGR it's a sealed unit.

[redbull2k]

how many turns did you do?