Manifold Absolute Pressure (MAP) Sensor
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The MAP sensor is a variable capacitor sensor that is supplied a 5-volt reference signal by the PCM and returns a voltage signal to the PCM relative to the intake manifold pressure. The sensor voltage increases as the pressure increases. The MAP sensor allows the PCM to determine the engine boost to calculate fuel quantity. In addition, the MAP signal is used to control smoke by limiting fuel quantity during acceleration until a specified boost pressure is obtained, and is used by the PCM for EGR system calculations and control.
A MAP signal concern detected by the PCM causes the PCM to calculate an estimated manifold pressure based on known engine conditions.