Suzuki Grand Vitara Service Manual page 146

1A-139 Engine General Information and Diagnosis:
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) to 150 °C (302 °F)
• Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
1) Connect scan tool to DLC with ignition switch turned OFF.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Increase vehicle speed to 50 – 60 mph, 80 – 100 km/h. (engine speed: 2500 – 3000 r/min.)
4) Keep above vehicle speed for 10 min. or more (Throttle valve opening is kept constant in this step).
5) Stop vehicle and check if DTC / pending DTC exists using scan tool. If not, check if catalyst monitoring test has
been completed using scan tool. If not in both of above checks (i.e., no DTC / pending DTC and catalyst
monitoring test not completed), check vehicle condition (environmental) and repeat Step 3) through 5).
DTC Troubleshooting
NOTE
Before this trouble shooting is performed, read the precautions for DTC troubleshooting referring to
"Precautions For DTC Troubleshooting: ".
Step
1 Was "Engine and Emission Control System Check"
performed?
2 Exhaust system visual check
1) Check exhaust system for leaks, damage and loose
connection.
Is it in good condition?
3 HO2S-2 output voltage check
1) Check output voltage of HO2S-2 referring to "DTC
P0137 / P0138: O2 Sensor (HO2S) Circuit Low Voltage /
High Voltage (Sensor-2): ".
Is check result satisfactory?
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Action
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Yes
Go to Step 2.
Go to Step 3.
Replace exhaust
manifold (built in warm
up three way catalytic
converter) and exhaust
center pipe (built in
three way catalytic
converter).
No
Go to "Engine and
Emission Control
System Check: ".
Repair or replace
defective part.
Check "BRN" and/or
"YEL" wires for open
and short, and
connections for poor
connection.
If wires and connections
are OK, replace HO2S-
2.