Iat (Intake Air Temperature) Sensor - Mercury MerCruiser D2.8L D-Tronic Service Manual

EDI DIAGNOSIS

IAT (Intake Air Temperature) Sensor

Scan Code:
Blink Code:
Malfunction Indicator Lamp:
CIRCUIT DESCRIPTION:
The IAT sensor and MAP (Manifold Absolute Pressure) 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 5 volt signal 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 Scan Code P1110.
55
64
Page 5E-30
a
a - IAT / MAP Sensor Assembly
b - IAT Signal
c - 5 Volt Reference Signal
d - MAP Signal
e - Sensor Ground
f - To Throttle Position Sensor
CKT PIN
Sensor Ground
IAT Signal
SERVICE MANUAL NUMBER 22
P1110
1112
ON
GRN/BLK
GRN
40
WHT/YEL
55
BLU/WHT
f
NAME
90-860074--1 FEBRUARY 2002
64
b
c
41
d
e
75340