Mercedes-Benz C400 Turbocharger Boost Sensor Replacement Cost

Boost pressure sensors are not common points of failure, and the average sensor will last well over 100,000 miles. In fact, there are replacements of these sensors ranging into the 170,000 mile range for several vehicles. Unfortunately, there is no way to extend the life of the boost pressure sensor, but most will not require replacement in either case.

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. Most times, these sensors will be in working order, but they do fail at random, so they must be tested.

Boost pressure sensors are simply replaced by removing them from their mounting location, disconnecting the single electronic connector, and installing the new sensor. However, this may call for some components of the vehicle to be removed, as these are often placed in hard to reach areas.

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, but there are other components that may cause theses faults.

Many turbocharged engines will use only the manifold absolute pressure sensor instead of the boost pressure sensor. For this reason, it is very important to understand the entire turbocharger system before attempting repair.

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 or underboost condition, it may be more cost effective to have diagnosis performed. If the boost sensor is known to be faulty, replacement is a quick and easy job for the DIY mechanic when the sensor is in an easy to reach location.