4-72 FI SYSTEM DIAGNOSIS
Step 1
HO2 sensor heater power supply circuit check
1) Turn the ignition switch OFF.
2) Disconnect the HO2 sensor coupler
1
. (
4-93)
3) Check for proper terminal connection to the HO2 sensor cou-
pler.
4) If connections are OK, turn the ignition switch ON.
5) Measure the voltage between O/W wire and ground.
09900-25008: Multi circuit tester set
Tester knob indication: Voltage (
)
HO2 sensor heater power supply voltage:
Battery voltage
(
+
terminal: O/W –
-
terminal: Ground)
Is check result OK?
Step 2
HO2 sensor circuit check
1) Turn the ignition switch OFF.
2) Remove the seat. (
8-5)
3) Disconnect the ECM couplers
1
.
1
YES
Go to Step 2.
NO
Repair or replace the O/W wire.
1
2
