Navistar International DT 466 Diagnostic/Troubleshooting Manual page 396

392 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
The ECT sensor provides a feedback signal to the
ECM indicating engine coolant temperature.
ECM monitors the ECT signal to control the following
features:
• Engine Warning and Protection System (EWPS)
• Cold Ambient Protection (CAP)
• Idle Shutdown Timer (IST)
• Cold idle advance
• Coolant compensation
During engine operation, if the ECM recognizes that
the ECT signal is greater or less than the expected
value it will set a Diagnostic Trouble Code (DTC).
Coolant Temperature Compensation
Coolant temperature compensation reduces fuel
delivery if ECT is above cooling system specification.
The reduction in fuel delivery begins when ECT
reaches approximately 107 °C (225 °F). A relatively
rapid reduction of 15% will be achieved as the ECT
reaches approximately 110 °C (230 °F).
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Fuel reduction is calibrated to a maximum of
The 30% before standard engine warning or optional
warning/protection is engaged.
shutdown occurs, a DTC is stored in the ECM
memory.
NOTE: Coolant temperature compensation may be
disabled in emergency vehicles that require 100%
power on demand.
Engine Warning and Protection (EWPS)
The EWPS is an optional feature that can be enabled
or disabled.
the operator of an overheat condition and can be
programmed to shut down the engine.
The red ENGINE lamp will come on when ECT
reaches approximately 109 °C (228 °F). A warning
buzzer will sound when ECT reaches approximately
112 °C (234 °F). The engine will shut down when the
ECT reaches approximately 112 °C (234 °F), if 3-way
protection is enabled.
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
If warning or
When enabled, the EWPS will warn