Test P: Service Engine Soon Indicator Never/Always On
WARNING: This page is about a different car, the 2000 Ford Mustang and 1999 Ford Mustang. However, it is still accessible from the selected car via links, so may be relevant.
Connect New Generation Star (NGS) tester to Data Link Connector (DLC). Turn ignition switch to RUN position. Using NGS tester, select instrument cluster active command MIL. Trigger MIL active command on. If SERVICE ENGINE SOON indicator illuminates, repair powertrain control concern. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. If SERVICE ENGINE SOON indicator does not illuminate, replace bulb or instrument cluster as necessary.