Ground Circuit Checks

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.

Using an ohmmeter, check ground circuits to PCM for continuity to ground. See WIRING DIAGRAMS article to determine PCM ground terminals. See PCM LOCATIONS table. If continuity is not present, repair open circuit to ground.
Using a voltmeter, touch negative lead to a good ground. Touch positive lead to each ground terminal. With vehicle running, voltmeter should indicate less than one volt. If voltage reading is more than one volt, check for open circuit, corrosion, or loose connection on ground lead.