Knock Sensor (KS): MPV
WARNING: This page is about a different car, the 2001 Mazda Protege, 2001 Mazda Millenia, 2001 Mazda MX-5 Miata, 2001 Mazda MPV, and 2001 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.
Disconnect KS connector. Using ohmmeter, measure resistance between KS terminals "A" (Red wire) and "B" (Black wire). Resistance should be about 560,000 ohms at 68°F (20°C). If resistance is not as specified, replace KS.