DTC P1487 - Manifold Absolute Pressure (Map) Sensor Solenoid Valve, Open Or Short Circuit: Condition

WARNING: This page is about a different car, the 1997 Mazda Millenia. However, it is still accessible from the selected car via links, so may be relevant.

DTC is set ECM detects open or short circuit in MAP sensor solenoid valve system when ignition switch is on. Possible causes are:

MAP sensor solenoid valve malfunction.
Open or short circuit between MAP sensor solenoid valve and main relay.
Open circuit between terminal No. 4P on Engine Control Module (ECM) and terminal "B" (White/Green wire) on MAP sensor solenoid valve.