2006 SUZUKI SX4 P0171

Downloaded from www.Manualslib.com manuals search engine 1A-102 Engine General Information and Diagnosis:
3Wire 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
Ω?Go to Step 4. “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.
4HO2S-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?Go to Step 5. “BRN” wire is shorted to
other circuit.
5HO2S-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?Go to Step 6. Repair HO2S-2 circuit. If
circuit is OK, substitute
a known-good ECM and
recheck.
6Exhaust system check
1) Check exhaust system for exhaust gas leakage.
Is it OK?Go to Step 4 in “DTC
P0171 / P0172: Fuel
System Too Lean /
Rich”.
If it is in good condition,
go to Step 8.Repair leakage of
exhaust system.
7Air intake system check
1) Check air intake system for clog or leak.
Is it OK?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.Repair or replace air
intake system. Step Action Yes No

Downloaded from www.Manualslib.com manuals search engine Engine General Information and Diagnosis: 1A-103
DTC P0171 / P0172: Fuel System Too Lean / RichS6RW0D1104036
DTC Detecting Condition and Trouble Area
DTC Confirmation Procedure
WARNING!
• When performing a road test, select a place where there is no traffic or possibility of a traffic
accident and be very careful during testing to avoid occurrence of an accident.
• Road test should be carried out by 2 persons, a driver and a tester, on a level road.

NOTE
Check to make sure that following conditions are satisfied when using this “DTC Confirmation
Procedure”.
• Intake air temperature at engine start: –10 °C (14 °F) to 80 °C (176 °F)
• Intake air temperature: –10 °C (14 °F) to 70 °C (158 °F)
• Engine coolant temperature: 70 °C (158 °F) or more
• Altitude (barometric pressure): 2500 m, 8200 ft or less (560 mmHg, 74.4 kPa or more)

1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and print Freeze Frame Data or write them down using scan tool.
3) Clear DTC using scan tool.
4) Start engine and warm up to normal operating temperature.
5) Operate vehicle with condition as noted freeze frame data for 5 min.
6) Stop vehicle and check DTC and pending DTC.DTC detecting condition Trouble area
DTC P0171:
Total fuel trim is higher than specified value or short term fuel trim is higher
than specified value for more than 1 min.
(2 driving cycle detection logic)
DTC P0172:
Total fuel trim is lower than specified value or short term fuel trim is lower
than specified value for more than 1 min.
(2 driving cycle detection logic)• Vacuum leakage
• Exhaust gas leakage
• Fuel pressure out of specification
• Fuel injector malfunction
• Heated oxygen sensor-1 malfunction
• MAF sensor malfunction
• ECT sensor malfunction

Downloaded from www.Manualslib.com manuals search engine 1A-104 Engine General Information and Diagnosis:
DTC Troubleshooting
NOTE
Before this troubleshooting is performed, read the precautions for DTC troubleshooting referring to
“Precautions for DTC Troubleshooting”.

Step Action Yes No
1Was “Engine and Emission Control System Check”
performed?Go to Step 2. Go to “Engine and
Emission Control
System Check”.
2Is there DTC(s) other than fuel system (DTC P0171 /
P0172)?Go to applicable DTC
diag. flow.Go to Step 3.
3Intake system and exhaust system for leakage check
Are intake system and exhaust system in good condition?Go to Step 4. Repair or replace
defective part.
4Fuel pressure check
1) Check fuel pressure referring to “Fuel Pressure Check”.
Is check result satisfactory?Go to Step 5. Repair or replace
defective part.
5Fuel injectors and its circuit check
1) Check fuel injectors referring to “Fuel Injector Inspection
in Section 1G”.
Is check result satisfactory?Go to Step 6. Faulty injector(s) or its
circuit.
6Visual inspection
1) Check MAF sensor and air intake system.
• Objects which block measuring duct and resistor of
MAF sensor.
• Other air flow which does not pass MAF sensor.
Are they in good condition?Go to Step 7. Repair or replace
defective part.
7MAF sensor for performance check
1) With ignition switch turned OFF, install scan tool.
2) Start engine and warm up to normal operating
temperature.
3) Check MAF value using scan tool (Refer to “Scan Tool
Data” for normal value.).
Is each value within specified range?Go to Step 8. Go to “DTC P0101:
Mass Air Flow Circuit
Range / Performance”.
8ECT sensor for performance check
1) Check ECT sensor referring to Step 3 and 4 of “DTC
P0118: Engine Coolant Temperature Circuit High”.
Is check result satisfactory?Go to Step 9. Faulty ECT sensor or its
circuit.
9HO2S-1 for performance check
1) Check HO2S-1 referring to Step 3 of “DTC P0131 /
P0132: O2 Sensor (HO2S) Circuit Low Voltage / High
Voltage (Sensor-1)”.
Is check result satisfactory?Substitute a known-
good ECM and recheck.Faulty HO2S-1 or its
circuit.