Neon L4-2.0L SOHC (1995)
Manifold Pressure/Vacuum Sensor: Description and Operation
Manifold Absolute Pressure Sensor Operation
Fig. 4 Intake Air Temperature Sensor And MAP Sensor
The PCM supplies 5 volts direct current to the MAP sensor. The MAP sensor converts intake manifold pressure into voltage. The PCM monitors
the MAP sensor output voltage.
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As vacuum increases, MAP sensor voltage decreases proportionately
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As vacuum decreases, MAP sensor voltage increases proportionately
Key ON
At key ON -- during cranking, before the engine is started, the PCM determines atmospheric air pressure from the MAP sensor voltage.
Engine Running
While the engine operates, the PCM determines intake manifold pressure from the MAP sensor voltage.
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Based on MAP sensor voltage and inputs from other sensors, the PCM adjusts spark advance and the air/fuel mixture.
The MAP sensor mounts to the intake manifold (Fig. 4).
CIRCUIT OPERATION
From the Powertrain Control Module (PCM), circuit K6 supplies 5 volts to the Manifold Absolute Pressure (MAP). Circuit K6 connects to cavity
43 of the PCM, and cavity 1 of the sensor connector.
Circuit K1 delivers the MAP signal to the PCM. Circuit K1 connects to cavity 29 of the PCM, and cavity 3 of the MAP connector.
The PCM provides a ground for the MAP sensor signal (circuit K1) through circuit K4. Circuit K4 connects to cavity 51 of the PCM connector,
and splices to cavity 2 of the sensor connector.
