HOLDEN GEN III V8, Service Training

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GEN III V8 ENGINE MANAGEMENT
DTC Information
The status of the diagnostic test and the related DTC messages can be viewed by using Tech 2 The
combination of messages is dependent on the status of the diagnostic test The following is a list of the DTC
information messages
• History: This messages indicates that the DTC has been stored in memory as a valid fault
• MIL SVS or Message Requested: This message indicates the DTC has requested the illumination of the
Check Powertrain lamp (MIL)
• Last Test Failed: This message indicates that the last diagnostic test failed during the current ignition cycle
This message remains until the diagnostic test passes, the DTCs are cleared or the ignition is turned off
• Test Failed Since Code Cleared: This message indicates that the diagnostic test failed at least once since
the DTC was cleared
• Not Run Since Code Cleared: This message indicates the diagnostic test related to this DTC has not been
run since the DTCs have been cleared The status of the system cannot be determined since a trip for the
DTC diagnostic test has not occurred
• Failed This Ignition: This message indicates that the diagnostic test related to the DTC has failed this
ignition cycle
Conditions to Set DTCs
A DTC sets when the enable criteria are met, the diagnostic test is run and the results of the test are outside the
PCM parameters
Conditions to Clear DTCs
There are three methods for clearing DTCs from the PCM memory
Method 1 :
Tech 2 can be used to clear DTC information This also clears freeze frame / failure record data, and statistical
PCM filters This is the preferred method to clear DTCs
Method 2:
If the battery positive or earth to the PCM is interrupted, all current information concerning the DTC, including
freeze frame / failure records, statistical filters and system status information may be lost
NOTE: The PCM retains memory for an extended period of time with the battery disconnected. This is
not the preferred method for clearing DTCs.
Method 3:
If the fault that caused the DTC to be stored in the PCM memory has been corrected, the Diagnostic Executive
begins to count the warm-up cycles Once it has counted forty consecutive warm up cycles with no further faults
detected, the DTC is automatically cleared from the PCM memory
PCM Sleep Test
After the ignition switch is turned OFF, the PCM will continue to operate for several seconds During this shut
down, the PCM will set the IAC valve to a position to be used on the next start-up, de-energise all the solenoids
and relays etc and go to sleep The Tech 2 scan tool will display updated data until the sleep mode is activated
then the PCM will no longer send out serial data and the Tech 2 scan tool will display DLC Data Lost
PCM Learning Ability
The PCM has a learning ability which allows the PCM to make corrections for minor variations in the engine or
the transmission system to improve dnveability
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