C44" Ho2 Sensor (Ho2S) Circuit Malfunction (E-02, 19, 54) - Suzuki AN400 Service Manual

4-42 FI SYSTEM

"C44" HO2 SENSOR (HO2S) CIRCUIT MALFUNCTION (E-02, 19, 54)

DETECTED CONDITION
During O2 feedback control, O2 sensor voltage is
higher than the specification or lower than the speci-
fication.
(Without the above range.)
The heater circuit disconnection is detected during
engine operation, or no electrical power is supplied
from battery.
INSPECTION
Step 1
1) Remove the foot board. (#7-19)
2) Turn the ignition switch OFF.
3) Check the HO2 sensor coupler for loose or poor contacts.
4) Insert the copper wires to the HO2 sensor lead wire coupler.
5) Warm up the engine enough.
6) Measure the HO2 sensor output voltage at the coupler
(between B/G and Y/W wires) when idling condition.
7) Also, measure the HO2 sensor output voltage while
holding the engine speed at 3 000 r/min.
$ HO2 sensor output voltage at idle speed:
0.4 V and less ( + B/G – - Y/W)
HO2 sensor output voltage at 3 000 r/min:
0.6 V and more ( + B/G – - Y/W)
! 09900-25008: Multi circuit tester set
& Tester knob indication: Voltage (')
Is the voltage OK?
YES Go to Step 2
NO Replace the HO2 sensor with a new one.
POSSIBLE CAUSE
• HO2 sensor or its circuit open or short.
• Fuel system malfunction.
• ECM malfunction.