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 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: 

• EGR solenoids.
• No torque converter clutch lock-up.