Hardware Limited Operational Strategy (HLOS)
WARNING: This page is about a different car, the 1995 Lincoln Mark VIII. However, it is still accessible from the selected car via links, so may be relevant.
HLOS mode is used when system fault(s) is too extreme for Failure Mode Effects Management (FMEM) mode to handle. If a number of system or sensor failures are present and PCM is not receiving enough information to operate, PCM will switch to HLOS mode. PCM will output fixed values to allow operation of vehicle. Driveability concerns will be present. PCM will not output diagnostic trouble codes in this mode.