1998 Buick Century Crank

Yes or eliminate it, it's locate on the right side of the engine below the exhaust manifold.
Use a volt meter set on 2-volt scale, test the ckp sensor while cranking, you should get 2 volts while cranking, test at the icm by unplugging the sensor input connector and testing across the leads. If the voltage is as specified, the fualt may be the ICM, if not check the CKP at the sensor, if voltage is not 2v change sensor, if it is, check the wires.