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Discussion Starter · #1 ·
I wrote before about this because May I upsoluted my 3B2 Passat 1.8T (APU engine code) model year 2000 made at the end of 1999, has all stock except the ECU (Bosch # 0 261 206 452) program from upsolute, aparently the only one available for my ECU.

The problem is usually I get the next error:

17964 - Charge Pressure Control: Negative Deviation
P1556 - 35-00 - -

I don't understand why happens, all looks OK, I don't see leaks, I swaped my DV by a Forge, and all goes smooth.. also I changed N75

When the error happens, the boost pressure measured at 115 group allways says 1360mbar, when demanded pressure is anyone above..
Sometimes this error happens when the demanded pressure it's practically the real...

they changed once the program of my ecu but nothing.. until a few weeks ago that my local chiptuning dealer saw an ibiza 1.8T that throw the same error at the real pressure requested by the ecu, and the problem was the MAF sensor..

I changed my MAF by other damaged to get an error that makes the ECU ignore the MAF, the engine goes more smooth but sometimes still happens the negative deviation.. will disappear when I change to a new MAF sensor?

what do you think?
 

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Discussion Starter · #2 ·
please, see this log with graphs...
http://www.geocities.com/alberto-s/bertwagen/LOG-01-204-211-xxxc.xls

since I did upsolute reprogramming to my Passat 1.8T, allways throws boost negative deviation error, and all usual troubles were checked DV, N75, etc.. and changed once the program..
I was told an ibiza 1.8T had the same error giving the demanded boost and it had MAF problems..

I did logs, and I thought the diference in the 211 group was that the calculated value was 150 y the measured by MAF was 133, bad MAF and change it under warranty as it was changed not many time ago because previous MAF died, but not, it's contrary! the MAF is measuring 150 g/s (I think it's normal for chipped 1.8T) meanwhile the ECU calculates should enter only 133 g/s

in the 211 log of the died MAF shows 0,22 g/s in the first column, that's nothing, so I think it's the measured value..

What happens? why does this, what it's wrong to cause this? How can be solved?

mau be possible it's closing the throtle to avoid entering "so much" air and that causes negative deviation? in group 204 manifold pressure sometimes it's noticeably smaller than the measured before thottle..

say anything, soon better because today tuesday this afternoon i have to left the car at vw dealer to the appointment i requested to "try" they change the MAF...
 

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First of all, what does upsolute say?

What happens if you unplug the MAF? Does it run fine? When my MAF went out it was causing the car to go into "limp-mode" and I didn't get any boost at all. I unplugged it and aside from the check engine light and the MAF failure code in the ECU, the car performed fairly normally.

I saw your message posted on the vag-com yahoo board - by searching for your code I found another message with the same code problem. Have you checked the braided vacuum hose that runs from the center of the diverter valve to the manifold? At the age of the car, it's possible that it's damaged. It's a fairly common problem.

Good luck.
 

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Discussion Starter · #4 ·
upsolute only said something like it's problem of the car, try this other program.. and also nothing... and after my upsolute distributor told me try a Forge (I tried with all spring rates for it, now I "wear" the red spring (the hardest) that's because there is some spikes when I release throttle)

the problem it's now the MAF looks good :???: if the 1st column of the 211 group it's the measured g/s :???: but ECU calculates less...

I tried my previous died MAF and the car goes similar, maybe smooth sometimes because there is not MAF that sends neither higher or lower values than calculated by ECU.. but still happens the same negative deviation error..

that hose looks ok, but I don't know why it could cause less boost, it only could make excess of boost by not opening DV...

:cry:
 

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Discussion Starter · #5 ·
also I tried bypass the N249 and still had the error
 

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Discussion Starter · #6 ·
somebody can show me other cars 211 group logs? also 204? and 002?

thanks
 

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try logging block 3 to see what the throttle plate is up to, although if it still requesting more boost than it is getting the plate is probably still 100%.

how many miles on the car, maybe the turbo/wastegate is dying? :nervous:

there is a block to see N75 duty cycle, something like 114 or 119, take a look and see if it is at 95% when the boost is only 1360 mbar....this would mean that the ECU is "trying" to get boost but it's not getting delivered by the turbo.

maybe you have a bad charge pressure sensor?
 

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Discussion Starter · #8 ·
i don't think it's dying, that car it's the less used at home, has only 40.000 km

i checked before the n75 duty, also changed, and it's 95% at full boost, but less at 1360mbar... the 1360mbar only stays when the error happen that boost it's the requested by the ecu..

i'll look the group 3... what mean 100% in that block?

about pressure sensor, i think maybe isn't because at group 204 the pressure at intercooler and the pressure at manyfold it's the same until at high speeds the pressure at manifold it's slighty less, but how could I check it? sensor at intercooler and at manifold are swapable? I don't remember now how it's the manifold sensor..

seeing the graph1 of my log, do you think I have the MAF OK? 150 g/s it's good value for a Passat 1.8T with 058 145 703 K turbo (it's the same as 170hp Passat AWM and AudiA4 AMB USA engines)? it's to decide if today I left the car or not to try to change it at vw...

nobody else have block 211 logs? i would like how it's the calculated value for the MAF of a car without problems..

also, could you tell me what values in what channels should be ok for lamba? time ago I got a lambda resistance too high error several times, but not now... how can I check? my car seems that hasn't any test procedure ¿? it has only 1 lambda sond but it's DBW..

many thanks :bow:
 
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