How to Test a Crankshaft Position Sensor

A car with its hood up exposing the engine.
What You'll Need
What You'll Need

If your car engine fails to start properly, there could be a problem with the crankshaft position sensor. The crankshaft position sensor measures the crankshaft position and speed.

Step 1 - Test the Voltage Output

To test if it your crankshaft position sensor is working properly, you have to test the voltage output. Once that is done, you can compare the readings with manufacturer specifications.

Step 2 - Wiring the Voltmeter

If the voltmeter is equipped with needle probes, the wires at the sensor connector need to be back probed.

Step 3 - Set the Multimeter

Set a digital multimeter to the AC minivolts range and crank the engine. A normal reading would be 200mV, but again this should be matched with manufacturer specifications. In case the car’s manual states a resistance value, you can check the sensor without having to crank the engine as well.

Step 4 - Set the Meter

Set the meter to ohms and check the resistance with what is specified in the service manual. If the test results are within specifications, you should check the sensor's electrical connector and the wiring harness. The trigger wheel located on the crankshaft or damper could have damaged or missing teeth. Any of these components could trigger a crankshaft position sensor to trouble code.

Completing the above tests thoroughly will let you know if the crankshaft position sensor is working or not. If it's not working, it's time to make some repairs.