DTC P1451: Barometric Pressure Sensor Performance Problem
WARNING: This page is about a different car, the 1997 Suzuki X-90. However, it is still accessible from the selected car via links, so may be relevant.
Turn ignition off. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Clear DTC(s). Start engine. Increase engine speed to 2000 RPM momentarily. Return engine to idle and run for one minute. If DTC(s) reset, replace PCM and retest system. If DTC(s) do not reset, check for an intermittent problem. See TESTS W/O CODES article.