3.16
ELECTRONIC FUEL INJECTION
CRANKSHAFT POSITION SENSOR
(CPS)
Operation Overview
The engine speed sensor is essential to engine operation,
constantly monitoring the rotational speed (RPM) and position
of the crankshaft.
A ferromagnetic 60-tooth ring gear with two consecutive teeth
missing is mounted on the flywheel. The inductive speed sensor
is mounted 1.0 ± 0.26 mm (0.059 ± 0.010 in.) away from the
ring gear. During rotation, an AC pulse is created within the
sensor for each passing tooth. The ECU calculates engine speed
from the time interval between the consecutive pulses. The two-
tooth gap creates an “interrupt” input signal, corresponding to
specific crankshaft position. This signal serves as a reference for
the control of ignition timing by the ECU. Synchronization of
the CPS and crankshaft position takes place during the first two
revolutions each time the engine is started. This sensor must be
properly connected at all times. If the sensor fails or becomes
disconnected for any reason, the engine will stop running.
CPS Test
The crankshaft position sensor is a sealed, non-serviceable
assembly. If fault code diagnosis indicates a problem with the
CPS, test and correct as follows:
1. Remove the seat and left-hand side panel.
2. Locate and disconnect the CPS harness connector on the
left side of the vehicle just below the ECU.
3. Connect an ohmmeter between the pin terminals as shown.
A resistance value of 860 Ω ± 10% at room temperature
(20
° C, 68° F) should be obtained.
4. If resistance is correct, check the mounting, toothed ring
gear (damage, runout, etc.), and flywheel key.
CPS Replacement
1. Disconnect sensor harness connector (see “CPS Test”).
2. Using a 6 mm hex wrench, remove the retaining bolt and
remove the sensor from the magneto cover.
3. Install the new sensor using a light coating of oil on the O-
ring to aid installation.
4. Torque the retaining bolt to specification.
CPS
“Removed”
Disconnect
Crankshaft Position Sensor:
860Ω ± 10% (20° C, 68° F)
= T
CPS Retaining Bolt Torque:
7 ft. lbs. (10 Nm)
Measure resistance
at these two pins
CPS Connector
CPS
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