Suzuki SX4 Service Manual page 144

1A-94 Engine General Information and Diagnosis:
Step
4 HO2S-1 ground check
1) Disconnect connector from HO2S-1 with ignition switch
turned OFF.
2) Check for proper connection to HO2S-1 connector at
"BLK/RED", "WHT", "BLK/WHT" and "ORN" wire
terminals.
3) If connections are OK, measure resistance between
"ORN" wire terminal of HO2S-1 connector and engine
ground.
Is measured resistance less than 5
5 Wire circuit check
1) Turn OFF ignition switch.
2) Remove ECM from its bracket with ECM connectors
connected.
3) Measure resistance between "WHT" wire terminal of
HO2S-1 connector and "C01-10" terminal of ECM
connector.
Is resistance less than 5
6 Wire circuit check
1) Disconnect connectors from ECM with ignition switch
turn OFF.
2) Measure resistance between "WHT" wire terminal of
HO2S-1 connector and vehicle body ground.
Is resistance infinity?
7 HO2S-1 signal circuit check
1) Measure voltage between "WHT" wire terminal of HO2S-
1 connector and vehicle body ground.
Is voltage 0 V?
8 HO2S-1 heater circuit check
1) Check HO2S-1 heater circuit referring to "DTC P0031 /
P0032: HO2S Heater Control Circuit Low / High
(Sensor-1)".
Is circuit in good condition?
9 Exhaust system check
1) Check exhaust system for exhaust gas leakage.
Is it OK?
10 Air intake system check
1) Check air intake system for clog or leak.
Is it OK?
Action
Ω
?
Ω
?
Yes
Go to Step 5.
Go to Step 6.
Go to Step 7.
Go to Step 8.
Go to Step 9.
Go to Step 4 in "DTC
P0171 / P0172: Fuel
System Too Lean /
Rich".
If it is in good condition,
go to Step 10.
Replace HO2S-1
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
"ORN" wire is open or
high resistance circuit.
Poor "C01-57" terminal
connection. Faulty ECM
ground.
If they are OK,
substitute a known-
good ECM and recheck.
"WHT" wire is high
resistance circuit or
open circuit. Poor "C01-
10" terminal connection.
Faulty ECM ground. If
they are OK, substitute
a known-good ECM and
recheck.
"WHT" wire is shorted to
ground circuit.
"WHT" wire is shorted to
other circuit.
Repair HO2S-1 circuit.
Repair leakage of
exhaust system.
Repair or replace air
intake system.