Navistar International DT 466 Diagnostic/Troubleshooting Manual page 503

7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
The IST feature provides several advantages when
enabled. Reduced emissions, fuel consumption, and
engine wear are all direct results from the IST strategy.
There are four states of the IST electronic operation.
• Idle shutdown timer indicates to the on-board
electronics that the vehicle has the following
features:
• OFF – turned off at all times.
• PTO available – allows prolonged engine idle
shutdown when engine is in low idle and PTO
is disabled.
• No engine load – allows prolonged engine idle
shutdown when engine is in low idle / no load
condition.
• Tamper proof – prohibits operator over-ride.
• Idle shutdown time indicates the programmed
value of engine idle time before engine will
shutdown.
• Maximum ambient intake air temperature
indicates maximum value of ambient intake air
temperature programmed to shutdown engine.
This feature prevents engine shutdown due to air
conditioner usage.
• Minimum ambient intake air temperature –
indicates minimum value of ambient intake air
temperature programmed to shutdown engine.
This feature prevents engine shutdown due to
cold ambient temperature.
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Fault Detection / Management
The IST feature is internal to the ECM. The
subsystems that contribute to the IST strategy have
their own fault codes. The fault code for the IST is not
a system diagnostic trouble code. The IST fault code
is only set to indicate that the IST has been activated
and the engine has shutdown.
IST Diagnostic Trouble Codes (DTCs)
DTCs are read using the EST or by counting the
flashes from the amber and red ENGINE lamp.
DTC 324
IST enabled engine shutdown
• DTC 324 is set by the ECM when the engine
has been shutdown due to exceeding the
programmed idle time criteria. The IST feature
must be enabled for DTC 324 to be displayed.
NOTE: DTC 324 does not indicate any system or
circuit DTCs. Diagnostic checks are not required for
DTC 324.
Tools
• EST with MasterDiagnostics® software
• EZ-Tech® interface cable
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
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