Powertrain Control Hardware
Powertrain Control HardwarePowertrain Control Module (PCM)
The center of the electronic engine control (EEC) system is a microprocessor called the PCM. The PCM receives input from sensors and other electronic components. Based on information received and programmed into its memory, the PCM generates output signals to control various relays, solenoids, and actuators. The Tribute uses a 150-pin PCM which has 3 separate electrical harness connectors.
PCM Location
The PCM is located behind the instrument panel (cowl), center to both driver and passenger sides (access from the engine compartment).
Fuel Pump Driver Module (FPDM)
The FPDM receives a duty cycle signal from the PCM and controls the fuel pump operation in relation to this duty cycle. This results in variable speed fuel pump operation. The FPDM sends diagnostic information to the PCM on the fuel pump monitor circuit. For additional information on the fuel pump control and the fuel pump monitor, see RESETTING FUEL SYSTEMS.
Keep Alive Memory (KAM)
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. KAM remains powered when the key 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 electronically erasable programmable read only memory (EEPROM), stop functioning correctly. All modes of self-test are not functional at this time. The 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