Hardware Limited Operation Strategy (HLOS)

This system of special circuitry provides minimal engine operation should the PCM (mainly the central processing unit [CPU] or EEPROM) stop functioning correctly. All modes of self-test are not functional at this time. Electronic hardware is in control of the system while in HLOS.

HLOS Allowable Output Functions: -  

• spark output controlled directly by the crankshaft position (CKP) signal
• fixed fuel pulse width synchronized with the CKP signal
• fuel pump relay energized
• idle speed control output signal functional

HLOS Disabled Outputs To Default State: -  

• exhaust gas recirculation (EGR) solenoids
• no torque converter clutch lock-up