Mercedes-Benz W204 boost pressure fault and power limitation
W204 boost pressure fault and power limitation: what causes it?
The cause varies from car to car. Most often the fault is caused by the boost pressure sensor, a split charge air hose or intercooler hose, or a vacuum hose that controls boost pressure regulation. Less often the cause is the turbo's variable vane, which is stuck or broken.
How is a boost pressure leak found on the W204?
A smoke test reveals a leaking charge air hose or joint without taking parts apart. Also check that the charge air pipes are firmly attached at their joints and that the hoses are not cracked. Replacing the turbo does not fix the fault if the cause is a hose.
What should be noted when replacing the boost pressure sensor?
The car may have several similar-looking sensors, and a sensor with the same part number may be in a different location, so make sure you have the right sensor. Before installing, clean the sensor's hole with compressed air, because a blocked hole gives a wrong reading. After replacement, clear the fault code.