How to Tell If the Crankshaft Positioning Sensor Isn't Getting Powerby Kyle Sanstrom
The crankshaft sensor in modern passenger vehicles runs on 12 volts of DC power. The sensor should receive this power any time that a driver turns the ignition to the "ON" position. Possible causes for the sensor not receiving power include a blown fuse, frayed wire, a faulty powertrain control module and a bad ground or loose connection. When the crankshaft sensor is not receiving power, the engine will crank but not start. A digital multi-meter will let you determine whether the crankshaft sensor is receiving adequate power.
Turn the ignition to the "ON" position and place the vehicle in first gear (manual) or in park (automatic). Apply the emergency brake and wait at least 60 minutes for the engine to cool down.
Locate the crankshaft sensor. The location of this sensor may vary slightly depending upon the make/model of the vehicle, but it is always on the engine block near the crankshaft, usually a few inches above the oil pan. Consult a repair manual for your specific vehicle if it is difficult to locate.
Depress the plastic locking tab on the crankshaft sensor's electrical connector and remove it from the sensor.
Turn on the digital multi-meter and set it to "Volts DC."
Probe the positive voltage wire (usually pink or orange) on the sensor's connector with the positive (red) probe on the multi-meter. Ground the black multi-meter probe by touching it to the engine block or a ground wire on near engine.
Look at the readout on the multi-meter. It should read at least 11.5 to 12 volts. If it reads less than this, the crankshaft sensor is not receiving adequate power.
- Digital multi-meters are used to measure electricity in various forms. They can be purchased from auto parts and hardware stores.
Things You'll Need
- Digital multi-meter
Kyle Sanstrom has been writing professionally since 2008. His articles have been published on several websites including eHow and Automobile Insight. Sanstrom has undergone advanced automotive training at the Dunwoody College of Technology, holds an Associate of Arts in general studies from Century College and has more than 10 years of experience in all aspects of automotive repair and diagnosis.