The vehicle's computer uses the mass air flow (MAF) sensor to measure the air volume going through the air intake system in your Toyota Sienna. The data from this and other sensors determines fuel feed volume, cylinder fire and transmission shift time. Since the sensor is fairly accessible, you can restore engine performance in your minivan by replacing the failed MAF sensor right in your driveway and get your Sienna back on the road in a matter of minutes.
Open the hood, and locate the air cleaner housing box, which contains the air filter, at the front driver's side of the engine compartment. You will see the air flow meter on the top area of the cleaner housing next to the air cleaner hose toward the rear of the box.
Unplug the mass air flow sensor electrical connector.
Unfasten the two sensor mounting bolts with a ratchet, short ratchet extension and socket, and pull off the sensor from the air cleaner housing.
Unhook the clips on the air cleaner housing cover, and loosen the clamp securing the air cleaner hose to the housing cover with a slotted screwdriver. Move the cover aside, and remove the air filter inside.
Clean the inside of the air cleaner housing and air cleaner hose of debris, which may affect MAF sensor and engine performance if air is unable to flow properly.
Replace the air filter and cover on the air cleaner housing. Tighten the air cleaner hose clamp and hook the clips to secure to cover to the air cleaner housing.
Position the new mass air flow sensor in place, and thread the two mounting bolts finger tight. Tighten the bolts with the ratchet, short ratchet extension and socket.
Plug in the mass air flow sensor electrical connector, and close the hood.
