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.