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Home >> Jaguar >> 2015 >> XFR-S >> Repair and Diagnosis >> External Pages >> Different car >> Section 47 (Electronic Engine Controls - GTDI 2.0L Petrol -- XF/X250) >> Electronic Engine Controls - GTDI 2.0L Petrol >> Description And Operation >> Electronic Engine Controls - System Operation And Component Description (G1550549) >> Description >> Mass Air Flow (MAF) Sensor

Mass Air Flow (MAF) Sensor

WARNING: This page is about a different car, the 2015 Jaguar XF, 2014 Jaguar XF, and 2013 Jaguar XF. However, it is still accessible from the selected car via links, so may be relevant.
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The MAF sensor is located on the top cover of the air filter box and is secured with two screws. The sensor is downstream of the air filter and measures the air entering the clean air duct to the turbocharger.

The MAF sensor receives a 12V power supply from the BJB. Three further connections provide signal feedback to the ECM for intake air temperature and air volume.

The MAF sensor works on the hot film principle. Two sensing elements are contained within a film. One element is maintained at ambient (air intake) temperature, e.g. 25°Celsius (77°F). The other element is heated to 200°Celsius (392°F) above the ambient temperature, e.g. 225°Celsius (437°F). Intake air entering the engine passes through the MAF sensor and has a cooling effect on the film. The ECM monitors the current required to maintain the 200°Celsius (392°F) differential between the two elements and uses the differential to provide a precise, non-linear, frequency based signal which equates to the volume of air being drawn into the engine.

The MAF sensor output is a digital signal related to the mass of the incoming air. The ECM uses this data, in conjunction with signals from other sensors and information from stored fueling maps, to determine the precise fuel quantity to be injected into the cylinders.

The ECM checks the calculated air mass against the engine speed. If the calculated air mass is not plausible, the ECM uses a default air mass figure which is derived from the average engine speed compared to a stored characteristic map. The air mass value will be corrected using values for boost pressure, atmospheric pressure and air temperature.

If the MAF sensor fails the ECM implements the default strategy based on engine speed. In the event of a MAF sensor signal failure, any of the following symptoms may be observed:

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