Chrysler 1997 Stratus Convertible LHD, Service Manual, Page: 254 / 1196

The camshaft position sensor is mounted to the
rear of the cylinder head. The sensor also acts as a
thrust plate to control camshaft endplay.
CAMSHAFT POSITION SENSOR—2.5L
The PCM determines fuel injection synchronization
and cylinder identification from inputs provided by
the camshaft position sensor and crankshaft position
sensor. From the two inputs, the PCM determines
crankshaft position.
The 2.5L engine is equipped with a camshaft
driven mechanical distributor, containing a shaft
driven distributor rotor. The distributor is also
equipped with an internal camshaft position (fuel
sync) sensor (Fig. 15). This sensor provides fuel injec-
tion synchronization and cylinder identification to
the PCM.
The camshaft position sensor contains a hall effect
device called a sync signal generator. This sync sig-
nal generator detects a rotating pulse ring (shutter)
on the distributor shaft. The pulse ring rotates 180
through the sync signal generator. Its signal is used
in conjunction with the crankshaft position sensor to
differentiate between fuel injection and spark events.
It is also used to synchronize the fuel injectors with
their respective cylinders.
When the leading edge of the shutter enters the
sync signal generator, the interruption of magnetic
field causes the voltage to switch high. This causes a
sync signal of approximately 5 volts.
When the trailing edge of the shutter leaves the
sync signal generator, the change of magnetic field
causes the sync signal voltage to switch low to 0
volts.
Since the shutter rotates at half crankshaft speed,
it may take 1 engine revolution during cranking for
the PCM to determine the position of piston number
6.
ENGINE COOLANT TEMPERATURE SENSOR
The Engine Coolant Temperature (ECT) sensor has
one element. The sensor provides an input voltage to
the PCM. The sensor is a variable resistance (ther-
mistor) with a range of -40°F to 265°F. As coolant
temperature varies, the sensors resistance changes,
resulting in a different input voltage to the PCM.
The PCM contains different spark advance sched-
ules for cold and warm engine operation. The sched-
ules
reduce engine emissions and improve
driveability. Because spark advance changes at differ-
ent engine operating temperatures during warm-up,
all spark advance testing should be done with the
engine fully warmed.
The PCM demands slightly richer air-fuel mixtures
and higher idle speeds until the engine reaches nor-
mal operating temperature.
The engine coolant sensor input is also used for
radiator fan control.
INTAKE AIR TEMPERATURE SENSOR—2.4/2.5L
The Intake Air Temperature (IAT) sensor measures
the temperature of the air as it enters the engine.
The sensor supplies one of the inputs the PCM uses
to determine injector pulse-width.
The IAT sensor threads into the intake manifold
(Fig. 16) or (Fig. 17).
KNOCK SENSOR
The knock sensor threads into the side of the cyl-
inder block in front of the starter motor. When the
knock sensor detects a knock in one of the cylinders,
it sends an input signal to the PCM. In response, the
PCM retards ignition timing for all cylinders by a
scheduled amount.
Knock sensors contain a piezoelectric material
which constantly vibrates and sends an input voltage
(signal) to the PCM while the engine operates. As the
Fig. 15 Camshaft Position Sensor—2.5L Engine
Fig. 16 Intake Air Temperature Sensor and MAP
Sensor—2.4L
8D - 8 IGNITION SYSTEM
JX
DESCRIPTION AND OPERATION (Continued)