Na'urar firikwensin matsin lamba na shigar iska (ManifoldAbsolutePressureSensor), wanda daga baya ake kira MAP. An haɗa shi da na'urar firikwensin shigar iska tare da bututun injin. Tare da nau'ikan saurin injin daban-daban, yana iya jin canjin injin a cikin na'urar firikwensin shigar iska, sannan ya canza canjin juriya a cikin na'urar firikwensin zuwa siginar ƙarfin lantarki, wanda ECU za ta iya amfani da shi don gyara adadin allurar da kusurwar lokacin kunnawa.
A cikin injin EFI, ana amfani da na'urar auna matsin lamba ta hanyar shigar da iska don gano yawan shigar da iska, wanda ake kira tsarin allurar D (nau'in yawan saurin gudu). Na'urar auna matsin lamba ta hanyar shigar da iska ba a gano yawan shigar da iska kai tsaye kamar na'urar auna kwararar shigar da iska ba, amma a kaikaice ana gano ta. A lokaci guda, abubuwa da yawa suna shafar ta, don haka akwai wurare daban-daban a cikin ganowa da kulawa daga na'urar auna kwararar shigar da iska, kuma kuskuren da aka samu shi ma yana da takamaimansa.
Na'urar firikwensin matsin lamba na shigar ruwa tana gano cikakken matsin lamba na shigar ruwa a bayan maƙurar ruwa. Tana gano canjin cikakken matsin lamba a cikin maƙurar ruwa bisa ga saurin injin da nauyinsa, sannan ta mayar da shi zuwa ƙarfin sigina sannan ta aika shi zuwa sashin sarrafa injin (ECU). ECU tana sarrafa adadin allurar mai na asali bisa ga girman ƙarfin siginar.
Akwai nau'ikan na'urori masu auna matsin lamba da yawa, kamar nau'in varistor da nau'in capacitive. Ana amfani da Varistor sosai a cikin tsarin allurar D saboda fa'idodinsa kamar saurin amsawa, daidaiton ganowa mai yawa, ƙaramin girma da kuma shigarwa mai sassauƙa.
Siffa ta 1 ta nuna alaƙar da ke tsakanin na'urar firikwensin matsin lamba na varistor da kwamfuta. Siffa ta 2 ta nuna ƙa'idar aiki ta na'urar firikwensin matsin lamba na varistor, kuma R a Siffa ta 1 ita ce masu juriyar matsin lamba R1, R2, R3 da R4 a Siffa ta 2, waɗanda suka samar da gadar Wheatstone kuma an haɗa su tare da diaphragm na silicon. Diaphragm na silicon na iya canzawa ƙarƙashin matsin lamba mai ƙarfi a cikin manifold, wanda ke haifar da canjin ƙimar juriya na juriyar matsin lamba R. Mafi girman matsin lamba mai ƙarfi a cikin manifold, mafi girman nakasar diaphragm na silicon kuma mafi girman canjin ƙimar juriya na juriya R. Wato, canje-canje na injiniya na diaphragm na silicon ana canza su zuwa siginar lantarki, waɗanda da'irar da aka haɗa ke ƙaruwa sannan a fitar da su zuwa ECU.
