Iat Sensor (Intake Air Temperature) - Navistar International DT 466 Diagnostic/Troubleshooting Manual

7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS

IAT Sensor (Intake Air Temperature)

Figure 456 Function diagram for the IAT sensor
The function diagram for the IAT sensor includes the
following:
• IAT sensor
• Electronic Control Module (ECM)
• Fuel injector
• ENGINE lamp (amber)
Function
The Intake Air Temperature (IAT) sensor is a
thermistor sensor that is chassis mounted on the
air filter housing. The ECM supplies a 5 V reference
signal which the IAT sensor uses to produce an analog
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
voltage that indicates the intake air temperature.
The IAT sensor changes resistance when exposed
to different temperatures.
decreases, the resistance of the thermistor increases.
This causes the signal voltage to increase.
air temperature increases, the resistance of the
thermistor decreases. This causes the signal voltage
to decrease.
The IAT sensor provides a feedback signal to the ECM
indicating intake air temperature. The ECM monitors
the IAT signal to control the timing and fuel rate for
cold starting. The continuous monitoring by the IAT
sensor limits smoke emissions.
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
451
As air temperature
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