Mercury MerCruiser D2.8L D-Tronic Service Manual page 487

SERVICE MANUAL NUMBER 22
INTAKE AIR TEMPERATURE AND MANIFOLD PRESSURE SENSOR ASSEMBLY
Intake Air Temperature (IAT) Sensor
The Intake Air Temperature (IAT) sensor and MAP sensor form an assembly. The IAT
portion of the assembly is a thermistor (a resistor which changes value based on
temperature). Low temperature produces a high resistance, while high temperature causes
a low resistance.
The ECM supplies a fixed current to the sensor through a resistor in the ECM and measures
the voltage. The ECM voltage will be high when the intake air is cold, and low when the
intake manifold air is hot.
A failure in the IAT sensor circuit should set a Code P1110.
90-860074--1 FEBRUARY 2002
a - IAT Sensor
b - Harness Connector
c - Locking Tab
c
b
DESCRIPTION
a
Page 5A-21
75340