tion (Fig. 16 or Fig. 17). The sensor generates pulses
that are the input sent to the PCM. The PCM inter-
prets the camshaft position sensor input (along with
the crankshaft position sensor input) to determine
crankshaft position. The PCM uses the crankshaft
position sensor input to determine injector sequence
and ignition timing.
The camshaft position sensor determines when a slot
in the camshaft gear passes beneath it (Fig. 18 or Fig.
19). When metal aligns with the sensor, voltage goes
low (less than 0.5 volts). When a notch aligns with the
sensor, voltage spikes high (5.0 volts). As a group of
notches pass under the sensor, the voltage switches
from low (metal) to high (notch) then back to low. The
number of notches determine the amount of pulses. If
available, an oscilloscope can display the square wave
patterns of each timing events.
The camshaft position sensor is mounted to the top
of the timing case cover (Fig. 20 or Fig. 21). The bot-
tom of the sensor is positioned above the camshaft
sprocket. The distance between the bottom of
sensor and the camshaft sprocket is critical to
the operation of the system. When servicing the
camshaft position sensor, refer to the Turbo III,
3.3L and 3.8L Ignition System—Service Proce-
dures section in this Group.
CRANKSHAFT POSITION SENSOR
The crankshaft position sensor senses slots cut into
the transaxle driveplate extension (Fig. 22 or Fig. 23).
On Turbo III, there are a 2 sets of slots. Each set
contains 4 slots, for a total of 8 slots (Fig. 24). On 3.3L
and 3.8L engines, there are a 3 sets of slots. Each set
contains 4 slots, for a total of 12 slots (Fig. 25).
Fig. 16 Camshaft Position Sensor—Turbo III Engine
Fig. 17 Camshaft Position Sensor—3.3L and 3.8L
Engines
Fig. 18 Camshaft Gear—Turbo III Engine
Fig. 19 Camshaft Gear—3.3L and 3.8L Engines
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IGNITION SYSTEMS
8D - 29