Suzuki SX4 Service Manual page 110

1A-60 Engine General Information and Diagnosis:
Step
2 HO2S-1 heater power circuit check
1) Disconnect connector from HO2S-1 with ignition switch
turned OFF.
2) Check for proper connection to HO2S-1 at "BLK/WHT"
and "BLK/RED" wire terminals.
3) If wire and connection are OK, measure voltage
between "BLK/WHT" wire terminal and engine ground
with ignition switch turned ON.
Is voltage over 10 V?
3 HO2S-1 heater power circuit check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure resistance between "BLK/WHT" wire terminal
of HO2S-1 connector and "E01-29" terminal of ECM
connector.
Is resistance below 5
4 HO2S-1 heater drive circuit check
1) Measure resistance between "C01-46" terminal of ECM
connector and vehicle body ground.
Is resistance infinity?
5 HO2S-1 heater drive circuit check
1) Turn ON ignition switch.
2) Measure voltage between "C01-46" terminal of ECM
connector and vehicle body ground.
Is voltage 0 V?
6 HO2S-1 heater drive circuit check
1) Connect connector to HO2S-1 with ignition switch turned
OFF.
2) Turn ON ignition switch.
3) Measure voltage between "C01-46" terminal of ECM
connector and vehicle body ground with connector
disconnected from ECM.
Is voltage over 10 V?
7 HO2S-1 heater check
1) Disconnect HO2S-1 connector with ignition switch
turned OFF.
2) Check HO2S-1 heater resistance referring to "Heated
Oxygen Sensor (HO2S-1 and HO2S-2) Heater On-
Vehicle Inspection (If Equipped) in Section 1C".
Is resistance within specified value range?
8 HO2S-1 heater power circuit check
1) Connect connector to HO2S-1 with ignition switch turned
OFF.
2) Measure resistance between "E01-29" and "C01-46"
terminals of ECM connector.
It resistance below 12
Action
Ω
?
Ω
?
Yes
Go to Step 3.
Go to Step 4.
Go to Step 5.
Go to Step 6.
Go to Step 7.
Go to Step 8.
HO2S-1 heater circuit is
OK.
Substitute a known-
good ECM and recheck.
No
"BLK/WHT" wire is open
circuit or shorted to
ground circuit.
"BLK/WHT" wire is high
resistance circuit.
"BLK/RED" wire is
shorted to ground
circuit.
"BLK/RED" wire is
shorted to power circuit.
"BLK/RED" wire is open
circuit.
Replace HO2S-1.
"BLK/WHT", "BLK/RED"
and / or "BLK" wire is
high resistance circuit.