Follow us on Twitter and win Autohex II Scan Tool for Kia and Hyundai (worth 945.00 USD)

The Manifold Absolute Pressure(MAP) sensor is essentially a strain gaugeused to measure the pressure in the surge tank. Inside the sensor is a metaldiaphragm with a small wire attached. The diaphragm flexes according to changesin pressure. When the diaphragm flexes, the wire attached to it stretches,changing the resistance of the wire. The Engine control Module (ECM) appliesfive volts to the MAP sensor and measures the voltage drop across the sensor.Sensor output is in volts and as pressure decreases, the voltage drop acrossthe sensor increases. Since the MAP sensor is used as an air flow sensor,the sensor signal is an important input. The ECM uses the information to determinefuel amount and ignition timing.

The MAP sensor outputs a voltage which corresponds to the pressure inthe surge tank. The ECM checks whether this voltageis within a specifiedrange. The ECM will set P0105 and the Malfunction Indicator Lamp (MIL) willturn on if the MAP sensor output voltage has continued to be 4.5V or higher-corresponding to a surge tank pressure of 114kPa (17psi) or higher-for 4 sec. or to be 1.95V or lower-corresponding to a surgetank pressure of 50kPa (7.4psi) or lower — for 4 sec.