Diagnosis & Repair Procedure

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 P1450 resets, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION article. Retest system. If DTC P1451 resets, check Manifold Differential Pressure (MDP) sensor and vacuum passage referring to DTC P1408: MANIFOLD DIFFERENTIAL PRESSURE (MDP) SENSOR CIRCUIT MALFUNCTION  . If sensor circuit and vacuum passage are okay, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION article. Retest system. If codes do not reset, check for an intermittent problem. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.