Manifold Absolute Pressure Sensor

The Powertrain Control Module (PCM) supplies 5 volts to the Manifold Absolute Pressure (MAP) sensor on the 5-volt reference circuit. The signal circuit returns a portion of the reference voltage to the PCM depending on the pressure inside the intake manifold. The PCM also provides a ground on the low reference circuit. The PCM should detect a low signal voltage at a low MAP, such as during idle or deceleration. The PCM should detect a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at Wide Open Throttle (WOT). The PCM monitors the MAP sensor signal for voltage outside of the normal range.