DTC P1525 - Air By-Pass Solenoid Valve (Vacuum), 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 when open or short circuit is detected in air by-pass solenoid valve (vacuum) when ignition is on. Possible causes are:

Air by-pass solenoid valve (vacuum) malfunction.
Open or short circuit between terminal "A" on air by-pass solenoid valve (vacuum) and main relay.
Open or short circuit between terminal "B" on air by-pass solenoid valve (vacuum) and terminal No. 2M on Electronic Control Module (ECM).