Fuel Cut Control System (Millenia)

WARNING: This page is about a different car, the 2000 Mazda Protege, 2000 Mazda Millenia, 2000 Mazda MX-5 Miata, 2000 Mazda MPV, and 2000 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.

To check system operation, connect New Generation Star (49 T088 0A0) scan tool to Data Link Connector (DLC) No. 2. DLC 2 is located under left side of instrument panel, right of steering column. Ensure engine is at normal operating temperature. Allow engine to idle. Turn A/C switch off.
Using scan tool, access DIAGNOSTIC DATA LINK menu, and select PCM. Highlight and select PID/DATA MONITOR AND RECORD. Select INJR and INJL. Scan tool will measure and display fuel injector pulse width. Increase engine speed to 4000 RPM, then quickly close throttle valve.
Fuel injection pulse width should be zero milliseconds until engine speeds drops to about 1200 RPM, then pulse width should return to specification noted prior to increasing engine speed. If pulse width is as specified, A/C cutoff system is functioning properly.
If pulse width is not as specified, measure voltage at PCM terminals 3Q (ECT sensor circuit), 3X (closed throttle position switch circuit), 4AH and 4AL (crankshaft position sensor circuit). See PIN VOLTAGE/PID VALUE CHARTS article. Repair as necessary.