MANIFOLD ABSOLUTE PRESSURE SENSOR - MAP SENSOR

What is the MAP sensor?

This sensor is of the electric piezo type, which varies its resistance according to the vacuum produced by the motor.  There are manufacturers that use the IAT Sensor or MAT Sensor that are of the NTC (Negative Temperature Coefficient) type and this is incorporated in the MAP Sensor.

At normal ambient temperatures the temperature sensor resistance is about 2 ohms.

How does the MAP Sensor work?

The MAP sensor controls the delivery of fuel to the engine taking into account the state of charge and the acceleration demand. It is an electronic sensor, which constantly inspects the vacuum of the intake manifold; acting according to the vacuum value can deliver more or less voltage to the ECU (Engine Control Unit), which supplies the amount of fuel through the injectors. It consists of a piezoelectric sensor, which is located on top of an integrated circuit. It measures the variation of pressure or vacuum, and in turn delivers a voltage signal to the outside.

The Manifold Absolute Pressure Sensor (MAP) has 3 wires: one ground, a 5-volt power cable and the third wire work as a signal. The signal voltage can vary between 0.2 - 0.4 volts to 4.8 - 5.0 volts.

• When the motor is in deceleration, the output voltage of the sensor is less than 0.8 volts.
• If it is in steady idle mode, it may be at approximately 950 RPM, the output voltage is between 0.9 and 1.5 volts.
• When the motor is in acceleration, the output voltage of the MAP sensor goes from 1.5 to 5.0 volts, which indicates a low or no vacuum.