C 1500 Truck 2WD V8-5.3L VIN T (1999)
Manifold Absolute Pressure (MAP) Sensor: Description and Operation
Manifold Absolute Pressure (MAP) Sensor
The Manifold Absolute Pressure (MAP) sensor responds to changes in the intake manifold pressure. The pressure changes as a result of engine load and
speed. The map sensor converts this to a voltage output.
A closed throttle on engine coast down produces a relatively low map output voltage. A wide open throttle produces a high map output voltage. This
high output voltage is produced because the pressure inside the manifold is the same as outside the manifold. The MAP is inversely proportional to what
is measured on a vacuum gauge. The MAP sensor is used for the following:
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Altitude determination.
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Ignition timing control.
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Speed density fuel management default. DTC P0107 MAP Sensor Circuit Low Voltage or DTC P0108 MAP Sensor Circuit High Voltage set
when the PCM detects a malfunction in the MAP sensor circuit.
