Sensor, Manifold Absolute Pressure (Map): Operation

The Manifold Absolute Pressure (MAP) Sensor is a transducer that varies resistance according to changes in altitude and atmospheric conditions. The MAP Sensor reading gives the Powertrain Control Module (PCM) an indication of the current air pressure within the intake manifold. The PCM uses this information to calculate fuel delivery. The MAP Sensor functions as a typical 3-wire sensor using the following circuits:

• The MAP Sensor has a 5-volt reference circuit, a low reference (sensor ground) circuit and a signal circuit.
• The PCM supplies 5 volts to the MAP Sensor on a 5 volt reference circuit and provides a ground on a low reference circuit.
• The MAP Sensor provides an analog voltage signal to the PCM relative to the pressure changes.