Chrysler Sebring 2004 Service Manual page 1211

14 - 30 FUEL INJECTION
MAP SENSOR (Continued)
time the PCM sees Wide Open throttle, based upon
TPS angle and RPM it will update barometric pres-
sure in the MAP memory cell. With periodic updates,
the PCM can make its calculations more effectively.
The PCM uses the MAP sensor to aid in calculat-
ing the following:
• Barometric pressure
• Engine load
• Manifold pressure
• Injector pulse-width
• Spark-advance programs
• Idle speed
• Decel fuel shutoff
The MAP sensor signal is provided from a single
piezoresistive element located in the center of a dia-
phragm. The element and diaphragm are both made
of silicone. As the pressures changes the diaphragm
moves causing the element to deflect which stresses
the silicone. When silicone is exposed to stress its
resistance changes. As manifold vacuum increases,
the MAP sensor input voltage decreases proportion-
ally. The sensor also contains electronics that condi-
tion the signal
compensation.
The PCM recognizes a decrease in manifold pres-
sure by monitoring a decrease in voltage from the
reading stored in the barometric pressure memory
cell. The MAP sensor is a linear sensor; as pressure
changes, voltage changes proportionately. The range
of voltage output from the sensor is usually between
4.5 volts at sea level to as low as 0.3 volts at 26 in. of
Hg. Barometric pressure is the pressure exerted by
the atmosphere upon an object. At sea level on a
standard day, no storm, barometric pressure is 29.92
in Hg. For every 100 feet of altitude barometric pres-
sure drops .10 in. Hg. If a storm goes through it can
either add, high pressure, or decrease, low pressure,
from what should be present for that altitude.You
should make a habit of knowing what the average
pressure and corresponding barometric pressure is
for your area. Always use the Diagnostic Test Proce-
dures Manual for MAP sensor testing.
REMOVAL
REMOVAL - 4 CYLINDER
(1) Disconnect the negative battery cable.
(2) Disconnect electrical connector from MAP sen-
sor (Fig. 21).
(3) Remove two screws holding sensor to the
intake manifold.
REMOVAL - 2.7L
(1) Remove the negative battery cable.
and provide temperature
Fig. 21 GENERATOR AND MAP SENSOR
1 - Generator
2 - MAP Sensor
(2) Disconnect the electrical connector from the
MAP sensor (Fig. 22).
(3) Remove bolt from sensor.
Fig. 22 MAP SENSOR - 2.7L
(4) Remove sensor.
JR