Suzuki Baleno Manual page 1422

6-2-74 ENGINE GENERAL INFORMATION AND DIAGNOSIS (J18 ENGINE WITH WU TWC)
DTC DETECTING CONDITION AND TROUBLE AREA
DTC DETECTING CONDITION
Output waveform of HO2S-2 becomes similar to that of HO2S-1.
(2 driving cycle detection logic)
DTC CONFIRMATION PROCEDURE (P0420)
WARNING:
D When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
D
dent and be very careful during testing to avoid occurrence of an accident.
D Road test should be carried out with 2 persons, a driver and a tester, on a level road.
D
NOTE:
Check to make sure that the following conditions are satisfied when using this DTC CONFIRMATION PRO-
CEDURE.
D Intake air temp.: –75C (17.45F) or higher
D
D Altitude (barometric pressure): 2400m, 8000 ft or less (560 mmHg 75 kPa or more)
D
1) Connect scan tool to DLC with ignition switch 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
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).
TROUBLESHOOTING (DTC P0420)
STEP
1 Was ENGINE DIAG. FLOW TABLE performed?
2 Exhaust System Visual Inspection
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 Step 3 of
DTC P0136 Diag. Flow Table.
Is check result satisfactory?
ACTION
TROUBLE AREA
Exhaust system
D
Three way catalytic converter malfunction
D
HO2S-2 or its circuit malfunction
D
YES
Go to Step 2.
Go to Step 3.
Replace three way
catalytic converter.
NO
Go to ENGINE
DIAG. FLOW
TABLE.
Repair or replace.
Check "P" and "Bl"
wires for open and
short, and
connections for poor
connection.
If wires and
connections are OK,
replace HO2S-2.