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6.
Connect the battery cables to the batteries.
Crankshaft Position Sensor (CPS)
The crankshaft position sensor is located at the top of the cylinder block next to the flywheel. The sensor contains a magnet which
is positioned next to the flywheel's lower ring gear. This ring gear has missing teeth at specific locations. The close proximity of
the crankshaft position sensor magnet to the teeth allows a magnetic field to be created each time a tooth passes the sensor. This
field collapses and creates an AC voltage pulse. This AC pulse is sent to the propulsion control module (PCM). The timing and
frequency of these pulses allows the PCM to regulate ignition and fuel injector timing. If the crankshaft position sensor fails, the
engine will run rough or stop running.
Crankshaft Position Sensor Test
1.
Perform a visual inspection of the sensor. The tip of the sensor must be flush across the end; if not, replace the sensor.
2.
The tip of the sensor must be clear of metal debris (ring gear filings).
NOTE: A magnet is mounted in the sensor tip. If the magnet is missing, the sensor will not operate properly.
3.
Inspect the flywheel pattern for:
•
Excessive corrosion
•
The teeth should have square edges
•
Only one open space on either side of the pattern groups
4.
Replace the flywheel if it does not meet inspection requirements.
5.
Inspect the sensor pins and the wires coming from the connector. Look for broken, bent, or corroded pins at the sensor; and
loose, broken, or corroded wires at the connector.
6.
Disconnect the engine harness connector from the sensor. Use the DMT 2004 digital multimeter to measure the resistance
across the sensor pins. Replace the sensor if out of specification.
NOTE: If the engine problem occurs above 3000 RPM (runs rough, no high RPM), the ohm test of the crankshaft position
sensor may be good, but the crankshaft position sensor can still be defective.
c
b
a
DMT 2004 Digital Multimeter
Crankshaft Position Sensor
Resistance at 20 °C (68 °F)
90-8M0050731 MAY 2011
d
a -
Magnet
b -
CPS
c -
Pin 1
d -
Pin 2
17025
15146
91‑892647A01
300–350 ohms
Ignition
Page 2A-21
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Troubleshooting
