* No Engine Start: The CKP sensor tells the engine's computer (PCM or ECM) where the crankshaft is in its rotation. This is crucial for the PCM to know when to fire the spark plugs and inject fuel. Without this information, the PCM cannot properly time the ignition and fuel injection, resulting in a no-start condition.
* Intermittent Running/Rough Running: If the sensor is partially functioning or intermittently failing, the engine might start but run very roughly, misfire severely, stall frequently, or have difficulty idling. The timing of the ignition and fuel injection will be erratic and inaccurate.
* Check Engine Light: The malfunctioning CKP sensor will almost certainly trigger the Check Engine light, along with diagnostic trouble codes (DTCs) stored in the PCM's memory. A mechanic can read these codes to confirm the CKP sensor as the culprit.
In short, a faulty crank position sensor renders the engine largely inoperable. Replacing the sensor is usually the solution.
