Tip & How-To about Mercedes-Benz E-Class

MAP - Manifold Absolute air Pressure sensor

1.9) MAP- Manifold Absolute air Pressure (sensor)

What is it? The MAP sensor is a device tomeasure the relative air pressure drop in the inlet manifold, as compared toatmospheric air pressure, when the engine is running.

Where is it located? The MAP sensor is most frequently sited either remotely on the middle ofthe fire wall (bulkhead) at the back of the engine compartment, on the innerwing (fender), on the side of the air ducting or directly bolted on to theintake manifold plenum. A vacuum hosefrom the inlet manifold connects remotely located MAPs, but if sited on themanifold plenum there is a direct connection on its underside.

How does it work? When the engine is at idle the throttle plate is fully closed and thevacuum within the inlet manifold is at its greatest, 20 inches (~500mm) mercury.On older MAP designs, sealed bellows (as in a weather barometer) expand orcontract in response to pressure change and this moves an armature in or out ofan electrical coil. The voltage output fromthe coil reflects the position of the armature and therefore the air pressure.
Modern MAP sensors aresmall, membrane-mounted, solid-state, Piezo electronic, strain-gauge sensor devicesproviding the ECU with electrical signal corresponding to the absolute airpressure within the inlet manifold. The air pressure taken in conjunction withair temperature (IAT) provides the ECU with information on the overallmass of air taken in by the engine and it can therefore calculate theappropriate amount of fuel to inject, providing power whilst minimizingemissions. This device also helps adjustthe engine to accommodate pressure decrease with increase in altitude. In normally aspirated engines MAPs measureinlet pressure decrease in the inlet manifold relative to atmospheric pressure butin turbo charged engines MAPs are also capable of measuring the positive (over)pressure of air (boost) delivered to the inlet manifold from the turbo charger.

Symptoms of a faulty MAP
Associated OBD2 error codes DTCs: P0105 - P109; P0121, P0129; P0236 - P0238;P1296, P1297

  • Poor starting/erratic idling/engine stall - with the MAP not sending the correct inlet air pressure signals to the ECU, incorrect fuel injection volumes then result. The imbalance in the fuel/air ratio often leads to rough engine performance and poor starting and stall. The engine might be kept running at start up by pumping the accelerator pedal
  • Sluggish performance/power ceiling - the engine may seem to perform normally in the lower rev range but will severely run out of power above about 3000 rpm
  • Poor fuel economy. The ECU tends to supply an over rich fuel mix to the engine in the absence of signal from the MAP resulting in very poor fuel economy. The reason for this is that if the MAP has no signal this means no vacuum = fully open throttle = engine is under load. To match this 'open throttle' signal the ECU increases the injection cycle to supply more fuel.

How to Check? The device has three electricalpins, one for 5 volts reference, one for 0 volts ground and the third (themiddle one generally) is the 'signal' output. Put a voltmeter positive connector on the 'signal' pin of the connectedsocket (back probe by inserting a bit of wire). Apply suction to the vacuum input, even sucking on it with your mouth,should result in a measurable voltage output. At normal air pressure (open throttle) the voltage seen should be 0volts. As vacuum is applied the voltageoutput should change to about 5 volts (throttle closed at idle). If no transition seen the MAP is faulty.

How to Fix? Replace it


NEXT 1.10) IMR - Intake Manifold Runner valve

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How do you know if a map sensor is gone?


You test it.

  • Map Sensor Testing - YouTube www.youtube.com/watch?v=B8EVhFc5Yqw
    • BY RICHPIN06A
    • 6 MIN
    • 589K VIEWS
    2009-03-15 · Map Sensor Testing manifold absolute pressure ... This feature is not available right now. Please try again later.
  • Part 1 -How to Test the MAP Sensor with a Multimeter (GM 2 ... troubleshootmyvehicle.com > GM > 3.1L, 3.4L Testing the GM manifold absolute pressure (MAP) sensor on your GM 2.8L, 3.1L, or 3.4L V6 equipped car can be accurately done using only a multimeter and a vacuum ...
  • Testing MAP sensor - GM Forum - Buick, Cadillac, Chev ... www.gmforum.com/.../testing-map-sensor-280296
    • 1 POST
    • FIRST POST: 2009-03-30
    2009-03-30 · Possible indications of a bad MAP sensor. Late shifting or harsh shift, incorrect/rough idle, stalling, surging, lack of power. Check the following
  • Geeks On Cars: How to Test a Map Sensor www.geeksoncars.com > Do It Yourself Car Maintenance How to Test a Map Sensor. The manifold absolute pressure sensor, or MAP sensor, monitors the amount of air flowing through the air intake system.
  • Manifold Absolute Pressure MAP Sensors - AA1Car.com www.aa1car.com/library/map_sensors.htm Manifold Absolute Pressure MAP Sensors ... MAP sensors are called manifold absolute pressure sensors rather than intake vacuum sensors because they ...


  • Map Sensor Testing

    Mar 19, 2016 | Cars & Trucks

    1 Answer

    06 f250 5.4 code r107


    Do you mean p0107 ? If so that is P0107 Ford - Manifold Absolute Pressure/Barometric Pressure Sensor Low Input

    Possible causes
    - Faulty Manifold Absolute Pressure sensor
    - Manifold Absolute Pressure harness is open or shorted
    - Manifold Absolute Pressure sensor circuit poor electrical connection
    - Faulty Engine Control Module (ECM) help.jpg What does this mean?
    When is the code detected?
    The ECM has detected a performance fault with the MAP sensor
    Possible symptoms
    - Engine Light ON (or Service Engine Soon Warning Light)
    - Engine rough idle
    - Engine hesitation
    P0107 Ford Description
    The Manifold Absolute Pressure (MAP) sensor provides instantaneous manifold pressure information to the engine's Engine Control Module (ECM). The data is used to calculate air density and determine the engine's air mass flow rate, which in turn determines the required fuel metering for optimum combustion. A fuel-injected engine may alternately use a Mass Air Flow (MAF) sensor to detect the intake airflow.



    Jul 16, 2014 | 2002 Ford F250 Super Duty SuperCab

    1 Answer

    map sensor location


    Located on top cylinder on transmission side.The MAP sensor is located either directly on the intake manifold or it is mounted high in the engine compartment and connected to the intake manifold

    Check out related help links to MAP sensor and its problems:----
    Click the link below:-----

    MAF, IAT, MAP and Coolant Level Sensor problem all together on Mazda MPV? http://schematicsdiagram.blogspot.com/2011/12/maf-iat-map-and-coolant-level-sensor.html
    ----------

    Oldsmobile Manifold Absolute Pressure (MAP) Sensor...

    ---------

    How to test MAP sensor?

    ---------------
    Working of Manifold Absolute Pressure (MAP) Sensor...
    --------------These will help.Thanks.

    Nov 23, 2012 | Cars & Trucks

    2 Answers

    Po108 service code


    Hi,
    OBD II Fault Code
    • OBD II P0108
    Fault Code Definition
    The Manifold Absolute Pressure Sensor/Barometric Pressure Sensor measures the rise and fall of the air pressure inside the Intake Manifold. This provides critical data needed for the Power Train Control Module (PCM) to control the Air Fuel Ratio, the Ignition Spark Timing, and many components of the Emissions Control Systems. The Manifold Absolute Pressure/Barometric Pressure Sensor converts the Intake Manifold air pressure into a voltage that is high when the Intake Manifold air pressure is high and low when the Intake Manifold air pressure drops to a vacuum. The P0108 code indicates a high voltage input from the Manifold Absolute Pressure Sensor/Barometric Pressure Sensor to the Power Train Control Module.
    Symptoms
    • Check Engine Light will illuminate
    • In many cases, no abnormal symptoms may be noticed
    • In some cases, the engine may be hard starting and/or get poor fuel economy
    • In some cases, noticeably poor engine performance may occur
    Common Problems That Trigger the P0108 Code
    • Manifold Absolute Pressure Sensor/Barometric Pressure Sensor is defective
    • Intake Manifold vacuum leaks
    • Faulty or corroded Manifold Absolute Pressure Sensor/Barometric Pressure wiring or connections
    Common Misdiagnoses
    • Manifold Absolute Pressure Sensor/Barometric Pressure Sensor is replaced when the real cause is an Intake Manifold vacuum leak
    • Manifold Absolute Pressure Sensor/Barometric Pressure Sensor is replaced when the real cause is a stuck-open EGR Valve
    • Manifold Absolute Pressure Sensor/Barometric Pressure Sensor is replaced when the real problem is a defective Idle Air Control Motor, which causes a very low engine idle

    Jan 26, 2011 | Mazda MPV Cars & Trucks

    1 Answer

    I unplugged the Mass Airflow Sensor and my truck runs better. I'm told by parts suppliers there is no Mass Airflow Sensor. What part did I unplug and will it damage the engine to run without it?


    Most likely if there is no mass air sensor you actually unplugged the inlet air temperature sensor IAT. This is a little bead like thermistor that sits in the ducted air stream to measure incoming air temperature. Without an air mass sensor your engine will have instead a manifold absolute (air) pressure MAP sensor. This measures the absolute air pressure (the difference between the atmospheric air pressure outside and the drop in pressure inside) in the inlet manifold. The drop in pressure in conjunction with air temperature allows the engine control unit to calculate the amount of air in the engine to which it adds the correct amount of fuel per each injection cycle. The loss of the IAT signal is not critical as the ECU will assume a default value. However when extreme low temperatures are encountered the absence of the IAT may be become noticeable as the charge of air entering the engine will be denser and as a consequence the fuel mix will be much leaner; maybe to lean to start up.

    Sep 08, 2010 | 1998 Chevrolet S-10 Pickup

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