Monday, March 12, 2012

How To Test Mass Air Flow (MAF) Sensor on Ford?

Mass Air Flow (MAF) Sensor
OPERATION & TESTING Details are as follows:---

The MAF sensor directly measures the amount of the air flowing into the engine. The sensor is mounted between the air cleaner assembly and the air cleaner outlet tube.

The sensor utilizes a hot wire sensing element to measure the amount of air entering the engine. The sensor does this by sending a signal, generated by the sensor when the incoming air cools the hot wire down, to the PCM. The signal is used by the PCM to calculate the injector pulse width, which controls the air/fuel ratio in the engine. The sensor and plastic housing are integral and must be replaced if found to be defective.

The sensing element (hot wire) is one thin platinum wire wound on a ceramic bobbin and coated with glass. This hot wire is maintained at 392°F (200°C) above the ambient temperature as measured by a constant "cold wire''.


Fig. Airflow diagram and components of the Mass Air Flow (MAF) sensor


Fig. Mass Air Flow sensor terminal identification
  1. Using a multimeter, check for voltage by backprobing the MAF sensor connector. With the engine running at idle, verify that there is at least 10.5 volts between the VPWR and PWR GND terminals of the MAF sensor connector. If voltage is not within specification, check power and ground circuits and repair as necessary.
  2. Check voltage between the MAF and MAF RTN terminals. Voltage should be approximately 0.34-1.96 volts. If voltage is not within specification, the sensor may be faulty.

This will help.

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