HOLDEN GEN III V8 Manual

HOLDEN
GEN III V8 ENGINE MANAGEMENT

HOLDEN LTDA.C.N. 006893 232
SERVICE TRAINING
COPYRIGHT - HOLDEN LTD
Reproduction inwhole orinpartprohibited without written approval
February 2000

GEN IIIV8 ENGINEMANAGEMENT
CONTENTS
SUBJECT
GEN IIIV8 ENGINEMANAGEMENT

GEN IIIV8 ENGINEMANAGEMENT
NOTES
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GEN IIIV8ENGINE MANAGEMENT

GEN IIIV8 ENGINE MANAGEMENT
GENERAL INFORMATION
The GEN IIIV8 engineuses a Powertrain Control Module(PCM) tocontrol exhaust emissions while maintaining
excellent driveability andfuel economy. The PCM maintains a desired air/fuel ratio atprecisely 14.7to 1.To
maintain a 14.7to 1 airfuel ratio the PCM monitors the output signals from two oxygen sensors. The PCM will
either addor subtract fuel pulses based on the oxygen sensors output signal.This method offeed back fuel
control iscalled closed loop.
Inaddition to fuel control, the PCM alsocontrols the following systems.
•The IgnitionDwell
•The IgnitionTiming
•The IdleSpeed
•The Engine Electric CoolingFans
•The Electric FuelPump
•The Instrument PanelCheck Powertrain lamp
•The A/C Compressor Clutch
•The Automatic Transmission Functions
•The ManualTransmission Reverse Lockout
•Theft Deterrent
The PCM alsointerfaces with other vehicle control modules, such asthe Powertrain Interface Module (PIM),
Instruments, andthe BodyControl Module(BCM). The illustration onthe following page contains a listof the
various operating conditions sensed bythe PCM on the left, and the various systems controlled onthe right.
The PCMhasa built-indiagnostic system that identifies operational problems atwhich time itstores a
Diagnostic Trouble Code (DTC) andon most occasions alerts the driver byilluminating the Check Powertrain
Lamp(CPL) inthe instrument. Ifthe lampcomes on while driving, itdoes notmean that the engineshould be
stopped immediately, butthe cause ofthe lampcoming onshouldbechecked assoon asisreasonably
possible.The PCMhasbuiltinbackup systems thatinallbutthe most severe faults will allow the vehicle to
operate ina nearnormalmanneruntilrepairs can bemade.
Below the instrumentpaneltothe left ofthe steering column isa DatalinkConnector(DLC)which isused by
the assembly plantfor a computer "check-out" of the PCM system. The DLCisalsoused inservice to help
diagnose the system usingTech 2.
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GEN IIIV8 ENGINE MANAGEMENT
POWERTRAIN CONTROL MODULE
The Powertrain Control Module (PCM), islocated inthe engine compartment and constantly monitors the
information fromvarious sensors, and controls the engine and transmission operation, dependant on the
information received fromthese sensors The PCM performs the diagnostic functionof the system Itcan
recognise operational problems, alert the driver through the Check Powertrain Lampand store a Diagnostic
Trouble Code(s) that willidentify problem areas to aid the technician inmaking repairs The PCM supplies either
abuffered 5 or 12voltsto power various sensors or switches This isdone through resistance's inthe PCM
which are so high invalue that a testlight will not light when connected to the circuitInsome cases, even an
ordinary voltmeter will notgive an accurate reading because the meter's internal resistance istoo low
A10Meg Ohm input impedance digital voltmeter isrequired 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" inthe PCM The two exceptions to this are the fuelpump
relay control circuit and the automatic transmission pressure control solenoid (PCS) The fuelpump relay isthe
only PCM controlled circuit where the PCM controls the +12volts sent to the coil of the relay The earth side of
the fuelpump relay coil isconnected 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 IIIPCM does not contain a removable PROM, ituses an EEPROM (Flash Memory) which isnon
removable The PCM isprogrammed from the factorywith the proper calibrations forvehicle operation Inthe
event that the PCM isreplaced, or anupdated calibration isrequired to correcta 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 isaccomplished 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 FlashMemory isnot programmed or has malfunctioned
PCM Security Link
Once the PCM, PIM andor 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 isapplied to PCM terminals J1-20and J1-57at all times via fuse F31 and ignition voltage is
applied to PCM terminal J1-19via fuse F14whenever the ignition switch isinthe ON or START positions The
PCM isearthed fromterminalsJ1-01,J1-40, J2-01 andJ2-40 to earth points E5and E15
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GEN IIIV8 ENGINE MANAGEMENT
PCM FiveVolt Reference Circuits
The PCM has two fivevolt reference circuits The fivevolt reference circuit number one supplies fivevolts to the
following sensors
•The Throttle Position Sensor (J1 -08)
•The Manifold Absolute Pressure Sensor (J1-48)
•OilPressure Sensor (J1-07)
The fivevolt reference circuit number two supplies fivevolts to the following sensor
•The A/C Pressure Sensor (J1-45)
The PCM monitors the voltage on the 5 0 volt reference circuit This DTC sets ifthe voltage isout of range
Afailure ina FiveVolt Reference Circuits will set one of the following DTCs:
DTCP1635Five Volt Reference #1 Circuit
Conditions for running DTCP1635
•The ignition ison
Conditions for setting DTC P1635
•The fivevolt reference #1circuit isout of range
•All of the above conditions are present forgreater than 2 seconds
Action taken when DTCP1635Sets
•The PCM illuminates the Check Powertrain Lampwhen the diagnostic runs and fails
•The PCM records the operating conditions atthe time the diagnostic fails The PCM stores this information
inthe Freeze Frame/Failure Records
Conditions for clearing the Check Powertrain Lamp and DTC P1635
•The PCM turns the Check Powertrain LampOFF after one ignition cycle that the diagnostic runs and does
notfail
•A last test failed (Current DTC) clears when the diagnostic runs and does notfail
DTCP1639Five Volt Reference #2 Circuit
Conditions for running DTCP1639
•The ignition ison
Conditions for setting DTC P1639
•The fivevolt reference #2 circuit isout of range
•All of the above conditions are present forgreater than 2 seconds
Action taken when DTCP1639Sets
•The PCM illuminates the Check Powertrain Lampwhen the diagnostic runs and fails
•The PCM records the operating conditions atthe time the diagnostic fails The PCM stores this information
inthe Freeze Frame/Failure Records
Conditions for clearing the Check Powertrain Lamp and DTCP1639
•The PCM turns the Check Powertrain Lamp OFF after one ignition cycle that the diagnostic runs anddoes
not fail
•A last test failed (Current DTC)clears when the diagnostic runs and does not fail
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