Grand Cherokee 2WD L6-4.0L VIN S (1997)
Barometric Pressure Sensor: Description and Operation
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR-PCM INPUT
The Manifold Absolute Pressure (MAP) sensor reacts to absolute pressure in the intake manifold. It provides an input voltage to the Powertrain
Control Module (PCM). As engine load changes, manifold pressure varies. The change in manifold pressure causes MAP sensor voltage to
change. The change in MAP sensor voltage results in a different input voltage to the PCM. The input voltage level supplies the PCM with
information about ambient barometric pressure during engine start-up (cranking) and engine load while the engine is running. The PCM uses this
input along with inputs from other sensors to adjust air-fuel mixture.
Fig. 9 Throttle Body & Sensors
The MAP sensor is mounted on the side of the engine throttle body. The sensor is connected to the throttle body with a rubber L-shaped fitting.
