We recommend you yourself get this Suzuki Forenza diagnosed at a reputable smog check test & repair station in order to first get the diagnosis results.
Generic trouble code P0516 is not related to either the crankshaft sensor, nor the camshaft sensor. OBD II trouble code P0516 indicates a problem with the battery temperature circuit. P0516 - Battery Temperature Sensor (BTS) Circuit Low Input. The problem can be with the engine control unit (ECU), BTS signal circult, or BTS module. If in fact P0516 is the only trouble code causing the check engine light to illuminate, the diagnosis and repair should get the check engine light to turn off and your Suzuki pass the smog test.