map or maf?

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  • lickitysplit
    Member
    • Jan 2012
    • 37

    map or maf?

    Would anybody know which of these two sensors are in command of fuel trim calculations?
    Vehicle in question is an 01 Toyota rav4 2.0l also uses air fuel ratio sensors. Has both amap and a maf.
  • badcoupe
    Senior Member
    • Jan 2011
    • 218

    #2
    air fuel sensor makes the makes the ecm calculate over or under the base map that the ecm is setup to given any one set of operating parameters. Also the map may be used as a baro sensor as well. Check the baro reading vs actual baro in your area.

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    • Joe Rappa
      Snap-on DSD
      • Aug 2007
      • 2050

      #3
      I'm not sure I'd say that it is in charge of the fuel trims, but on any vehicle I have come across with both sensors, the PCM will rely on the MAF to determine how much fuel to add, and the MAP is used for EGR /engine vacuum diagnostics. So, if you have a fuel trim problem, look at the MAF before you look at the MAP.
      Joe
      "You don't build a reputation on what you're going to do"
      Henry Ford

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      • lickitysplit
        Member
        • Jan 2012
        • 37

        #4
        map or maf?

        Thnx for clarifying this with a speedy reply.

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        • Trindaddy
          Senior Member
          • Jan 2010
          • 339

          #5
          Try unplugging each and see what it does. Actually, MAF is definitely involved. Try sticking a smaller orifice in map and see what happens to trim. Sounds like fun.

          Neil

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          • gravygrabber
            Junior Member
            • Dec 2011
            • 5

            #6
            It's probably got a dirty MAF

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            • Witsend
              Banned
              • Nov 2012
              • 2942

              #7
              Rav 4

              If I had to guess what part would fix a problem without knowing what the codes and fuel trims are. I think the EEC pinwheel would point to the AF ratio sensor

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