Internal failure of the ignition switch may create a condition where the key reminder continues to chime even though the key is removed. In addition, the doors cannot be locked with the keyless entry system. Replacing the ignition switch with an updated switch is the typical repair.Google+
Car Problem Reports
Mazda Mazda3 Ignition Switch Failure May Cause Key Reminder to Chime Continuously
Mazda Mazda3 Problem
Average Mileage: 80,202 mi (30,000 mi - 101,215 mi)
key reminder will not cut off with the key remove?
The key reminder chimes even when key is not in ignition. I have to manually lock and unlock door with key.
Visitor, 2005 Mazda Mazda3, 70,000 mi
This problem happened to me, but the solution was quite simple. There was something wrong with the fuses. Fuses are only like $5 each.