Cold-sensitive turbo?

Hello,

I have had a Polo 9N with an ATD engine (100hp PD) since about a year ago, manufactured in 2002.

In the winter, the car occasionally went into limp mode, and the following error was found in the fault memory:
1 Fault Found:
17964 - Charge Pressure Control: Negative Deviation
P1556 - 35-10 - - - Intermittent

Unfortunately, I was never able to log the error when it occurred because it was quite sporadic.

According to my observations, the error usually occurs when the outside temperature is <5°C and the engine is not yet fully warmed up ( <90°C) at approximately 2000 rpm.

Therefore, based on what I've read so far about turbo problems, it could likely be due to 2 problems: LMM or a difficult-moving VTG turbo.

The control unit no longer enters the emergency mode since spring, but the engine sometimes has less power available.

Today, I wanted to test the ease of movement of the turbo via the vacuum line, but unfortunately, I couldn't find it.

Can anyone tell me where to find the VTG turbo, the adjusting rod, and the vacuum hose?

Here is a log file from my test drive today:
/download.php?id=2121

I would really appreciate any helpful tips Thank you.

freakyC64 wrote:

Based on what I've read so far about turbo problems, it seems to me that it could be due to 2 problems: LMM or a difficult-moving VTG turbo. Here is a log file from my test drive today: /download.php?id=2121

Hi,

Your log (5th gear) only seems to indicate a severely stuck VTG. And strangely, it seems to be stuck somewhere in the middle position...
The LMM values seem OK to me.

Quote:

Can anyone tell me where I can find the VTG turbo, the adjustment rod, and the vacuum hose?

You can find the intercooler with rod (top) and hose (bottom) behind the engine, above the right drive shaft.

You can also feel for it from above, or use a small mirror and light to look around the corner (in which case, remove the engine cover).

Once you've found the can, check immediately to see if your VTG rod is also at the closed position when in neutral. Otherwise, follow the articles by Rainer and Ulf on VTG. Then you'll know what the problem was.

Best regards,
Poldi