Powertrain Control Hardware

POWERTRAIN CONTROL HARDWARE

Fuel Pump Driver Module (FPDM)
The FPDM receives a duty cycle signal from the powertrain control module (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, refer to Powertrain Control Module (PCM) Outputs, Fuel Pump and Powertrain Control Module (PCM) Inputs, Fuel Pump Monitor. Powertrain Control Module (PCM) Outputs Powertrain Control Module (PCM) Inputs

Integrated Electronic Ignition (EI) System
The EI system consists of a crankshaft position (CKP) sensor, ignition coils, connecting wiring, and PCM. The coil on plug (COP) integrated EI system uses a separate coil for each spark plug and each coil is mounted directly onto the plug. The COP integrated EI system eliminates the need for spark plug wires, but requires input from the camshaft position (CMP) sensor.

Powertrain Control Module (PCM)

150-Pin PCM:

150-Pin PCM Power And Grounds (Part 1):

150-Pin PCM Power And Grounds (Part 2):

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 hybrid vehicle uses a 150 pin PCM which has 3 separate electrical harness connectors.

Powertrain Control Module (PCM) 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.

Powertrain Control Module (PCM) 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. The 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.

PCM Location
The PCM is located behind the instrument panel (cowl), center to both driver and passenger sides (access from the engine compartment).

Powertrain Control Module (PCM) Power and Ground Signals

Vehicle Buffered Power (VBPWR)
The VBPWR is a PCM supplied power source that supplies regulated voltage (10 to 14 volts) to vehicle sensors that run off 12 volts but cannot withstand VPWR voltage variations. It is regulated to VPWR minus 1.5 volts and is voltage limited to protect the sensors.

Vehicle Power (VPWR)
When the key is turned to the ON or START position, battery positive voltage (B+) is applied to the coils of the EEC power relay and power sustain relay (PSR). Since the other end of the coils are wired to ground, this energizes the coils and closes the contacts of the EEC power relay and PSR. VPWR is now supplied to the PCM and the EEC system as VPWR. When the key is turned to the OFF position, the PCM keeps the PSR energized until the normal power down sequence is completed.

Vehicle Reference (VREF) Voltage
The VREF is a positive voltage (about 5.0 volts) that is output by the PCM. This is a consistent voltage that is used by the 3-wire sensors.

Mass Air Flow Return (MAF RTN)
The MAF RTN is a dedicated analog signal return from the mass air flow (MAF) sensor. It serves as a ground offset for the analog voltage differential input by the MAF sensor to the PCM.

Signal Return (SIG RTN)
The SIG RTN is a dedicated ground circuit used by most EEC sensors and some other inputs.

Power Ground (PWR GND)
The PWR GND is an electric current path return for VPWR voltage circuit. The purpose of the PWR GND is to maintain sufficient voltage at the PCM.

Gold Plated Pins

NOTE: Damaged gold terminals should only be replaced with new gold terminals.

Some engine control hardware has gold plated pins on the connectors and mating harness connectors to improve electrical stability for low current draw circuits and to enhance corrosion resistance.