HYOSUNG AQUILA 250 FI, Service Manual, Page: 42 / 90

41
FI SYSTEM DIAGNOSIS 4-1-32
“C43” OXYGEN SENSOR HEATER CIRCUIT MALFUNTION
Oxygen sensor
heater voltage
Battery voltage
(
�
OB -
�
B )
( � OB - � Ground )
Is the voltage OK?
NO
YES
Replace the Oxygen sensor.
DETECTED CONDITION POSSIBLE CAUSE
Oxygen sensor heater signal is not input in ECU.
●
Oxygen sensor, Oxygen sensor heater circuit open
or short.
●
Oxygen sensor, Oxygen sensor heater malfunction.
●
ECU malfunction.
Tester knob indication : Voltage ( )
ECU Coupler
�
�
CODE
CODE
CODE
CODE
C43
CODE
CODE
[ 4 3 3 4 ]
● OB or B wire open or shorted to ground,
or poor
� or � connection.
● If wire and connection are OK,
intermittent trouble or faulty ECU.
● Recheck each terminal and wire harness
for open circuit and poor connection.
▣ ▣
INSPECTION
1) Remove the frame cover.
2) Turn the ignition switch “OFF” position.
3) Check the Oxygen sensor heater coupler for loose
or poor contacts.
If OK, then measure the Oxygen sensor heater
voltage.
4) Disconnect the coupler and then the ignition
switch “ON” position.
5) Measure the voltage between OB wire terminal
and B (or ground) wire terminal.