Possible Causes

WARNING: This page is about a different car, the 2003 Mazda Protege5 and 2003 Mazda Protege. However, it is still accessible from the selected car via links, so may be relevant.

Open circuit between VTCS solenoid valve and main relay.
Open or short circuit between VTCS solenoid valve and PCM.
PCM malfunction.
Poor connection at VTCS solenoid valve or PCM.
VTCS solenoid valve malfunction.