Caravan FWD V6-3.8L VIN L (1999)
Manifold Pressure/Vacuum Sensor: Description and Operation
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR-PCM INPUT
The PCM supplies 5 volts to the MAP sensor. The MAP sensor converts intake manifold pressure into voltage. The PCM monitors the MAP
sensor output voltage. As vacuum increases, MAP sensor voltage decreases proportionately. Also, as vacuum decreases, MAP sensor voltage
increases proportionately.
During cranking, before the engine starts running, the PCM determines atmospheric air pressure from the MAP sensor voltage. While the engine
operates, the PCM determines intake manifold pressure from the MAP sensor voltage.
Based on MAP sensor voltage and inputs from other sensors, the PCM adjusts spark advance and the air/fuel mixture.
MAP Sensor
MAP Sensor
