HOLDEN GEN III V8, Service Training

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GEN III V8 ENGINE MANAGEMENT
POWERTRAIN CONTROL MODULE
The Powertrain Control Module (PCM), is located in the engine compartment and constantly monitors the
information from various sensors, and controls the engine and transmission operation, dependant on the
information received from these sensors The PCM performs the diagnostic function of the system It can
recognise operational problems, alert the driver through the Check Powertrain Lamp and store a Diagnostic
Trouble Code(s) that will identify problem areas to aid the technician in making repairs The PCM supplies either
a buffered 5 or 1 2 volts to power various sensors or switches This is done through resistance's in the PCM
which are so high in value that a test light will not light when connected to the circuit In some cases, even an
ordinary voltmeter will not give an accurate reading because the meter's internal resistance is too low
A 1 0 Meg Ohm input impedance digital voltmeter is required to assure accurate voltage readings.
The PCM controls output circuits such as the injectors, IAC, and various relays, etc by controlling the earth
circuit through transistors or a device called a "Driver" in the PCM The two exceptions to this are the fuel pump
relay control circuit and the automatic transmission pressure control solenoid (PCS) The fuel pump relay is the
only PCM controlled circuit where the PCM controls the + 1 2 volts sent to the coil of the relay The earth side of
the fuel pump relay coil is connected to engine earth The PCM supplies current to the PCS and monitors how
much current returns to the PCM on a separate terminal The PCM also receives and transmits serial data via
the Powertrain Interface Module (PIM) and the serial data bus
The Gen III PCM does not contain a removable PROM, it uses an EEPROM (Flash Memory) which is non
removable The PCM is programmed from the factory with the proper calibrations for vehicle operation In the
event that the PCM is replaced, or an updated calibration is required to correct a vehicle's operating condition,
the new PCM or the new calibration will have to be down loaded to the PCM EEPROM (Flash Memory) Down
loading is accomplished through the vehicle DLC using the TECH 2 Service Programming System (SPS) and
the Technical Information System (TIS)
The service replacement PCM EEPROM (Flash Memory) will not be programmed DTC P0601 and P0602
indicates the Flash Memory is not programmed or has malfunctioned
PCM Security Link
Once the PCM, PIM and or BCM have been replaced, the new PCM, PIM and BCM must be security linked to
each other using Tech 2 and TIS
PCM Power Supplies
Battery voltage is applied to PCM terminals J1-20 and J1-57 at all times via fuse F31 and ignition voltage is
applied to PCM terminal J 1 - 1 9 via fuse F 1 4 whenever the ignition switch is in the ON or START positions The
PCM is earthed from terminals J1 - 0 1 , J1 -40, J2-01 and J2-40 to earth points E5 and E 1 5
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