What does fault code P0321 mean?

[LaGenevieve]

P0321 indicates an unreliable engine speed sensor signal, which is the most fundamental input signal for engine operation. It is used to calculate engine speed, determine ignition timing advance, and work in conjunction with the camshaft position sensor signal to identify the top dead center position of the first cylinder for ignition. If the engine speed sensor malfunctions, it will cause incorrect calculation of ignition timing advance, resulting in delayed or deviated ignition during engine starting. There are five possible causes for fault code P0321: 1. Damaged sensor itself. 2. Unreliable wiring connections. 3. Water or other foreign matter in the connector. 4. Abnormal signal disc movement of the crankshaft position sensor. 5. Presence of iron filings at the sensor test terminal.