The mass air flow sensor is an important feature of a Volvo's fuel-regulation system. This sensor is located near the air filter and has the job of regulating how much air is allowed to mix the gasoline combusted in the engine. An old or worn out mass air flow sensor will not let the proper amount of air into the engine, causing knocking and decreasing the Volvo's gas mileage. With a set of six-pointed star-shaped tools called Torx-head drivers you can install a new mass air flow sensor yourself.
Open the hood of your Volvo and disconnect the negative battery terminal with an adjustable crescent wrench; this will ensure that power is not being supplied to the mass air flow sensor.
Locate the plastic box that contains the car's air filter. This box has a large, approximately 5-inch-diameter hose connected to its side. The mass air flow sensor is attached to the side of this large hose.
Unplug the small hose that connects to the mass air flow sensor with a firm tug.
Use the Torx-head drivers to remove the two screws that hold the mass air flow sensor to the large hose. Set the old mass air flow sensor aside.
Attach the new mass air flow sensor to the large hose that leads to the air filter with the two screws. Plug the smaller hose back into the mass air flow sensor and reconnect the negative terminal of the battery to finish the job.
