The crankshaft position sensor (CKP sensor) on a 1994 Chevy Corsica is located on the
passenger side of the engine block,
near the crankshaft pulley. It's usually mounted fairly low, sometimes even partially obscured by other components. You'll likely need to get under the car for a clear view.
Because its exact location can vary slightly depending on the specific engine (2.2L or 2.5L), a repair manual specific to your vehicle's year and engine is recommended to pinpoint it precisely. A visual inspection with the help of diagrams in a manual is your best bet.
