Checking the turbine pressure Audi A6 C7 2.0 TFSI / A4 B8 1.8 TFSI using VAG-COM (english subtitles)
The turbine overpressure on 2.0/1.8 #TFSI engines should be about 0.8 bar or an absolute value of 1.8 bar (1800 hPa), this pressure should be created already at 1800-2000 rpm.
In my case, on #Audi A6 C7, the turbine blows 0.8-1 bar of overpressure, on A4 B8 only 0.6 bar, although the actual and set value converges, so I will deal with A4 additionally, perhaps a replacement of the valve N249 is required.
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Possible causes of turbine malfunction:
1) pressure control valve N75 (06F906283F) and pressure relief valve N249 (for A6C7 06H145710C, for A4B8 06H145710D)
2) wastegate valve in the hot part of the turbine, due to loose fitting, excess pressure exits into the exhaust
3) mechanical failure of the turbine (damage to the impeller or housing)
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Parameters to look at in VAG-COM:
Charge air pressure: specified value
Charge air pressure: actual value
These two values should be as close as possible and the actual value should not lag far behind in time and be typed as quickly as possible, for this it is most convenient to run the graph together with the engine speed.
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