Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Sensor, Crankshaft Position: Operation
Typical tone wheel (1) and Crankshaft Position (CKP) sensor (3) shown.
Engine speed and crankshaft position are provided through the Crankshaft Position (CKP) sensor. The sensor generates pulses that are the input sent to the Powertrain Control Module (PCM). The PCM interprets the sensor input to determine the crankshaft position. The PCM then uses this position, along with other inputs, to determine injector sequence and ignition timing.
The CKP sensor (3) is a hall effect device combined with an internal magnet. It is also sensitive to steel within a certain distance from it.
A tone wheel (target wheel) (1) is bolted to the engine crankshaft. This tone wheel has sets of notches (2) at its outer edge.
The notches (3) cause a pulse to be generated when they pass under the sensor. The pulses are the input to the PCM.
Depiction of good camshaft and crankshaft square wave signals for 6 cylinder engines.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.