BMW 428i Turbocharger Boost Pressure Solenoid Replacement Cost

These solenoids live in a very hot environment and are in use constantly as the engine is running. That said, it is expected that they have a higher than normal failure rate, but they are fairly resilient. The average mileage of replacement for several vehicles is between 45,000 and 160,000 miles, so it is very difficult to understand when to expect this repair.

If the turbocharger wastegate is not functioning, the technician will begin by inspecting for play at the wastegate control rod, wastegate actuator, and visually inspecting the boost pressure control solenoid. This will allow the technician to eliminate simple and common failures. However, if everything i mechanically sound and the wastegate can be actuated by vacuum, the turbocharger boost pressure control solenoid will be tested using a diagnostic scanner to cause the wastegate to vent boost pressure. If the overboost situation is not alleviated, the manifold absolute pressure sensor and boost sensor will be tested prior to replacing the solenoid.

The boost pressure control solenoid can be replaced by removing fasteners and vacuum lines, plus the electronic connector for the boost pressure control solenoid. New clamps will be used when installing the new solenoid, and the solenoid will be tested once installed to ensure the wastegate opens successfully.

RepairPal recommends thorough testing of the turbocharger and boost control system before replacing parts associated with these systems. The OBD trouble codes found stored on the ECM or PCM will only alert the technician to which component detected the failure, not which component has failed. If overboost is detected, the boost pressure sensor or manifold absolute pressure sensor may be incorrect as well.

Not all turbocharged vehicles will use the boost pressure control solenoid. In fact, nearly all older vehicles with turbocharged engines will use pneumatic operations to open the wastegate. Also, vehicles with externally vented wastegates may have the solenoid placed in a remote location, so understanding the components of the turbocharging system in use is important.

This is a difficult diagnosis for anyone without a diagnostic scanner. It can be done, but it will be very difficult. Since most people without a professional scan tool will likely begin replacing parts to diagnose an overboost condition, it may be more cost effective to have diagnosis performed. If the solenoid is known to be faulty, replacement is a quick and easy job for the DIY mechanic.