DTC P1450 & P1451: Barometric Pressure Circuit Malfunction Or Performance Problem (Esteem 1.8L)

Turn ignition off. Connect scan tool to Data Link Connector (DLC). If DTC P1451 is not present, replace PCM. If DTC P1451 is present, remove PCM. Turn ignition on, engine off. Measure voltage between PCM connector terminals E91-7 (Green wire) and C20-27 (Orange wire). About 3.9-5.0 volts should be present. Start and idle engine. About 1.4-2.4 volts should be present. If voltages are to specification, replace PCM. If voltages are not to specification, go to DTC P1408: MANIFOLD DIFFERENTIAL PRESSURE (MDP) SENSOR CIRCUIT MALFUNCTION (ESTEEM 1.8L)  .