HYOSUNG AQUILA 250 FI, Service Manual, Page: 32 / 90

31
FI SYSTEM DIAGNOSIS 4-1-22
“C17” or “C18” IAP SENSOR CIRCUIT MALFUNCTION
▣ ▣
INSPECTION
◈
Step 1
1) Remove the fuel tank.
2) Turn the ignition switch “OFF” position.
3) Check the IAP sensor NO.1 coupler
①
and NO.2
coupler
②
for loose or poor contacts.
If OK, then measure the IAP sensor input voltage.
DETECTED CONDITION
●
Clogged vacuum passage between throttle body
and IAP sensors.
● Air being drawn from vacuum passage between
throttle body and IAP sensors.
●
IAP sensor circuit open or shorted to ground.
● IAP sensor malfunction.
●
ECU malfunction.
POSSIBLE CAUSE
YES
NO
IAP sensor input
voltage
4.5 ~ 5.5 V
( � OB - � Ground )
( � OB - � BW)
Is the voltage OK?
Tester knob indication : Voltage ( )
C17
C18
CODE
CODE
①
②
[ 1 7 1 7 ]
[ 1
8 1 8 ]
IAP sensor voltage is out of the specified range.
0.1 V
�
Sensor voltage
�
4.8 V
NOTE :
Note that atmospheric pressure varies depending on
weather conditions as well as altitude.
Take that into consideration when inspecting voltage.
Go to Step 2.
● Loose or poor contacts on the
ECU coupler.
● Open or short circuit in the OB
wire or BW wire.
4) Disconnect the IAP sensor couplers NO.1
①
and
NO.2
②
.
5) Turn the ignition switch “ON” position.
6) Measure the voltage at the OB wire and ground.
If OK, then measure the voltage at the OB wire
and BW wire.