- The mass airflow sensor is attached to the air cleaner box under the hood, but its specific location varies from one model to the next. It may be inside or outside the air cleaner box and may be installed on any side. If you can't locate it by visually inspecting the air cleaner box inside and out, consult a repair or parts manual for your specific make and model of vehicle.
- Examine the mass air flow sensor carefully to determine exactly how it is held in place, as this may also vary among makes and models. The MAF unit is usually anchored in place with either a pair of screws, a pair of bolts or a series of metal clips that can be popped open with a flat-head screwdriver. You should also see a wiring harness plugged into the unit; this can usually be unplugged without tools, but it may also have metal clips or screws holding it in place. Carefully remove the wiring harness and the mounting assembly, then pull the mass airflow sensor completely away from the air cleaner box.
- Look into the mass airflow sensor unit, which is a short, wide aluminum cylinder. Inside the cylinder is a smaller compartment with an opening, and if you look in the opening, you should see two exposed wires. This small opening is the housing of the sensor itself, and it should have the greatest concentration of accumulated particles. Carefully set the unit on a work table and spray the exposed wires with specialized mass airflow sensor cleaner or with electrical connection cleaner. Most of the time, a couple of sprays of cleaner will immediately wash away and dissolve the buildup of particles. In some cases, the buildup will loosen but will remain stuck to the wires and sensor. When this happens, wait a few minutes and re-spray the sensor with cleaner or spray the sensor with a can of compressed air, which may blow the buildup away. Don't use brushes or other instruments to clean the sensor directly, as it is very delicate. Once the sensor is clean, allow it to air dry completely.
- Reconnect the wiring harness to the MAF, and reinstall any screws or clips that may have held it in place. Set the mass airflow sensor unit back on its mount and replace the screws, bolts or clips that attach it to the air cleaner box. If the MAF on your car is located inside the air cleaner box, be sure to replace the box lid tightly before closing the hood.
