Here's why:
* Intermittent Failure: The sensor might be failing intermittently. It might work fine for a while, then fail completely, causing the engine to stall. An intermittent fault doesn't always trigger a stored code. The computer needs to see a consistent problem before it sets a code.
* No Code Storage: Even if the failure is prolonged enough to trigger a code, the 1998 OBDII system isn't perfect. Sometimes, transient issues don't get logged.
* Engine's Reliance on the CKP: The crankshaft position sensor is crucial for the engine's timing. Without a signal, the engine control module (ECM) can't accurately control fuel injection and ignition timing. This will lead to a sudden stall. The car might even be hard to restart.
* Other Related Issues: A failing CKP sensor can sometimes mimic other problems, making diagnosis tricky and potentially preventing a specific code from being stored.
While a bad CKP sensor is a strong possibility, it's important to note that other components could cause similar symptoms. A thorough diagnostic check by a mechanic is recommended to pinpoint the exact cause. They'd check the sensor itself, its wiring, and even look at other components to rule out other potential issues.
