Powertrain Control Hardware

Powertrain Control Hardware

Keep Alive Random Access Memory (RAM)

The PCM stores information in keep alive RAM (a memory integrated circuit chip) about vehicle operating conditions, and then uses this information to compensate for component variability. Keep alive RAM remains powered when the ignition switch is off so that this information is not lost.

Hardware Limited Operation Strategy (HLOS)

This system of special circuitry provides minimal engine operation should the PCM [mainly the central processing unit (CPU) or FEEPROM] 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 cruise control output signal functional.

HLOS Disabled Outputs To Default State:
- EGR solenoids
- no torque converter clutch lock-up PCM Location:
- Behind instrument panel (cowl), center to both driver and passenger sides.

Integrated Electronic Ignition System (EI) The coil on plug (COP) integrated El system eliminates the need for spark plug wires but does not require input from the camshaft position (CMP) sensor.