Suzuki SX4 Service Manual page 152

1A-102 Engine General Information and Diagnosis:
Step
3 Wire circuit check
1) Turn OFF ignition switch.
2) Remove ECM from its bracket with ECM connectors
connected.
3) Measure resistance between "BRN" wire terminal of
HO2S-2 connector and "C01-11" terminal of ECM
connector.
Is resistance less than 5
4 HO2S-2 signal circuit check
1) Disconnect connectors from ECM with ignition switch
turned OFF.
2) Measure voltage between "BRN" wire terminal of HO2S-
2 connector and vehicle body ground.
Is voltage 0 V?
5 HO2S-2 heater circuit check
1) Check HO2S-2 heater circuit referring to "DTC P0037 /
P0038: HO2S Heater Control Circuit Low / High
(Sensor-2)".
Is circuit in good condition?
6 Exhaust system check
1) Check exhaust system for exhaust gas leakage.
Is it OK?
7 Air intake system check
1) Check air intake system for clog or leak.
Is it OK?
Action
Ω
?
Yes
Go to Step 4.
Go to Step 5.
Go to Step 6.
Go to Step 4 in "DTC
P0171 / P0172: Fuel
System Too Lean /
Rich".
If it is in good condition,
go to Step 8.
Replace HO2S-2
referring to "Heated
Oxygen Sensor (HO2S-
1 and HO2S-2)
Removal and
Installation (If Equipped)
in Section 1C".
If DTC still exists,
substitute a known-
good ECM and recheck.
No
"BRN" wire is high
resistance circuit or
open circuit. Poor "C01-
11" terminal connection.
If they are OK,
substitute a known-
good ECM and recheck.
"BRN" wire is shorted to
other circuit.
Repair HO2S-2 circuit. If
circuit is OK, substitute
a known-good ECM and
recheck.
Repair leakage of
exhaust system.
Repair or replace air
intake system.