Hyundai Sonata 1991 Shop Manual page 280

MPI SYSTEM
1. Disconnect the air flow sensor connectors.
2. Measure the resistance between the terminals 4 and 6.
Terminal 4 : Intake air temperature output
Terminal 6 : Sensor ground
Temperature °C (OF)
Resistance (kfl)
o
(32) 5.4-6.6
20 (68)
2.33-2.97
80 (176) 0.31-0.43
3. Measure the resistance while heating the sensor using a
hair drier.
Temperature °C (OF)
Resistance (kfl)
Higher Smaller
4. If the value deviates from the standard value or the resis-
tance remains unchanged, replace the air flow sensor assem-
bly.
AFS side connector
..
3
2
1 I I
6"" 5 4
K~
If l~
\
9
I
~ ~\
~ -;..~
I
I . .
(;0
~../,
Intake
aIr
~ -<..
Z temperature
~
sensor
,...
~1=::""-
J1Y084
31YOBS
Engine Coolant Temperature Sensor
Y31EEOA
The engine coolant temperature sensor installed in the engine
coolant passage of the intake manifold is a resistor-based sensor.
The ECU judges engine warm-up state by the sensor output volt-
age and provides optimum fuel enrichment when the engine is
cold.
Terminal 1
Terminal 2
3lY086
1. Remove the engine coolant temperature sensor from the
intake manifold.
2. With the sensing portion of the engine coolant temperature
sensor immersed in hot water, check resistance. The sensor
should be held with its housing 3 mm (0.12 in.) away from
the surface of the hot water.
31Y087
31-55