How do you check a crankshaft sensor?

To check the crankshaft sensor on a 1995 Buick LeSabre, you can follow these steps:

Locate the Crankshaft Sensor: The crankshaft sensor is typically located near the bottom of the engine, close to the crankshaft. It may be positioned behind the harmonic balancer or on the side of the engine block.

Inspect the Wiring and Connections: Start by inspecting the wiring harness connected to the crankshaft sensor. Ensure that the connectors are clean, free of corrosion, and properly connected. Check for any visible damage or fraying in the wiring.

Test the Crankshaft Sensor Signal: To test the crankshaft sensor signal, you'll need a digital multimeter (DMM) set to the AC voltage scale. Follow these steps:

a. Disconnect the electrical connector from the crankshaft sensor.
B. Insert the positive (red) lead of the multimeter into the connector's signal wire.
C. Ground the negative (black) lead of the multimeter to a suitable ground point on the engine.
D. Set the multimeter to measure AC voltage and crank the engine.

While cranking, you should see an AC voltage signal on the multimeter display. The specific voltage values can vary depending on the vehicle, so consult a repair manual or manufacturer's specifications for the expected range.

Check for a Consistent Signal: While monitoring the multimeter, ensure that the crankshaft sensor signal is consistent and stable during engine cranking. If the signal is erratic or absent, it could indicate a faulty crankshaft sensor.

Test Resistance (Optional): If necessary, you can also test the resistance of the crankshaft sensor using a DMM set to the resistance (ohms) scale. Again, consult a repair manual or manufacturer's specifications for the expected resistance values for your particular sensor. Measure the resistance across the sensor's terminals and compare it to the specified range.