The sensor is a hall effect device combined with an
internal magnet. It is also sensitive to steel within a
certain distance from it.
OPERATION
Engine speed and crankshaft position are provided
through the crankshaft position sensor. The sensor
generates pulses that are the input sent to the pow-
ertrain control module (PCM). The PCM interprets
the sensor input to determine the crankshaft posi-
tion. The PCM then uses this position, along with
other inputs, to determine injector sequence and igni-
tion timing.
The crankshaft position sensor detects slots cut
into the transmission driveplate extension. There are
3 sets of slots. Two sets contain 4 slots and one set
contains 5 slots, for a total of 13 slots (Fig. 7). Basic
timing is set by the position of the last slot in each
group. Once the Powertrain Control Module (PCM)
senses the last slot, it determines which piston will
be next at TDC from the camshaft position sensor
input. It may take the PCM one engine revolution to
determine crankshaft position.
The PCM uses crankshaft position reference to
determine injector sequence and ignition timing.
Once the PCM determines crankshaft position, it
begins energizing the injectors and coils in sequence.
The PCM uses the Crankshaft Position sensor to
calculate the following:
• Engine rpm
• TDC number 1 and 4
• Ignition coil synchronization
• Injector synchronization
• Camshaft-to-crankshaft misalignment (Timing
belt skipped 1 tooth or more diagnostic trouble code)
CAMSHAFT POSITION SENSOR
DESCRIPTION
The camshaft position sensor is mounted in the
front of the timing case cover (Fig. 8) or (Fig. 9). It is
a hall effect device.
Fig. 5 Coil Capacitor
1 – IGNITION COIL CAPACITOR
Fig. 6 Crankshaft Position Sensor Location
1 – CRANKSHAFT POSITION SENSOR
Fig. 7 Timing Slots
1 – TORQUE CONVERTER DRIVE PLATE
2 – SLOTS
LH IGNITION SYSTEM 8D - 3
DESCRIPTION AND OPERATION (Continued)
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