Detection Condition
WARNING: This page is about a different car, the 2003 Mazda MPV and 2002 Mazda MPV. However, it is still accessible from the selected car via links, so may be relevant.
PCM monitors input voltage from generator and battery positive terminal. DTC is set, when engine is running and generator output voltage is more than 18.5 volts or battery voltage is more than 16 volts for 5 seconds.