The intake manifold pressure sensor is measuring the negative air pressure inside the intake pipe after it passes the throttle valve. The pressure value is recorded by an evaluation circuit via the differential pressure of two diaphragm pressure chambers. With the air pressure data the engine management calculates the turbo boost pressure for turbocharged engines and the fuel injection values for naturally aspirated engines.

In case of a defective intake manifold pressure sensor the engine management system will issue a diagnostic trouble code and ignite the check engine light. In addition to that the engine will lack power, use more fuel or even go into emergency mode.

The boost pressure sensor is located inside the air stream so it is prone to pollution. Other common failure reasons can be corrosion or cable damage.