can someone please help, my car has been looked at a few times, when i
accelerate there is a whoosing noise coming from the front of the car, it
went to get fixed they said the turbo hose had burst then they said they
couldnt find anything wrong with the hoses, it has just had a new air mass
meter fitted because it was losing power, it has got some power back but
feels like there should be more, dont know where this air is escaping
from, it sounds like you have the windows down when accelerating, but it
is definatley coming from under the bonnet.
There are a number of hoses that the dealer can not see from a casual
inspection. They need to pressure test the system to find a leak.
You should also suspect a broken waste gate actuator. They can be replaced but
need to pull the turbo.
Also might have a bad 710N valve.
Well, I had a similar experience: hissing/vacuum-like noise, and some
loss of power. If you're in the same boat, then if you read out your ECU
codes, you will see:
17965 - Charge Pressure Control: Positive Deviation
P1557 - 35-00 - -
(note, this does not set the CEL)
Cause for me was a split "vacuum" hose (but sometimes vacuum hoses are
under pressure in these cars. The leak was near where the vacuum lines T
off that feed the N75 boost regulation valve. This causes the boost
pressure to spike. Once that happens, the ECU limits max boost to ~4psi
to ensure no overboost is generated. That results in the crappy power
For my split hose, at idle (when the "vacuum" system really is under
vacuum), just look around a bit. My hose was split so badly it had
collapsed, and hissing noises were pretty evident.
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