Suzuki 2000 Grand Vitara SQ625 Service Manual page 210

DTC DETECTING CONDITION AND TROUBLE AREA
DTC DETECTING CONDITION
Output waveform of HO2S (S-2) becomes similar to that of
HO2S (S-1).
DTC CONFIRMATION PROCEDURE
NOTE:
Check to make sure that following conditions are satisfied when using this DTC CONFIRMATION PROCE-
DURE.
WARNING:
D When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and very careful during to avoid occurrence of an accident.
D Road test, should be carried out with 2 person, a driver and tester, on a level road.
D Intake air temperature: between –14 C and 70 C (6.8 F and 158 F)
D Atmospheric pressure: higher than 560 mmHg (Altitude: lower than 2790 m (9150 ft))
D Following DTCs are not detected: P0100 (No.33, 34), P0110 (No.23, 25), P0115 (No.14, 15), P0130, P0133,
P0134 (No.13), P0135, P0136, P0141, P0335, P0460, P0500 (No.24), P1450 and P1451
(1) With ignition switch OFF, connect scan tool.
(2) Turn ON ignition switch and clear DTC by using scan tool if any.
(3) Start engine and warm up to normal operating temperature.
(4) Increase vehicle speed to 56 km/h (35 mph) or more.
(5) Keep above vehicle speed for 5 min. (Throttle valve operating is kept constant in this step.)
(6) Increase vehicle speed to 80 – 100 km/h (50 – 60 mph). (engine speed; 2500 – 3000 r/min.)
(7) Keep above vehicle speed for 1 min. (Throttle valve operating is kept constant in this step.)
(8) Stop vehicle and check DTC and pending DTC by using scan tool.
DTC TROUBLESHOOTING
STEP
1 Was "ENGINE DIAG. FLOW TABLE" performed?
2 Exhaust System Visual inspection:
(1) Check exhaust system for leaks, damage and loose.
Is it in good condition?
3 HO2S BANK-1 (BANK-2) SENSOR-2 Circuit check:
(1) Check "R/B" and "Gr/Y" wire ("R/Y" and "Gr/Y" wire).
Are they in good condition?
4 (1) Replace BANK-1 (BANK-2) HO2S SENSOR-2.
(2) Perform DTC confirmation procedure.
Is DTC P0420 (P0430) detected?
5 (1) Replace BANK-1 (BANK-2) warm up TWC converter.
(2) Perform DTC confirmation procedure.
Is DTC P0420 (P0430) detected?
ACTION
ENGINE (H25 ENGINE) 6-1-99
TROUBLE AREA
TWC converter
Exhaust system
HO2S (SENSOR 2)
HO2S (SENSOR 2) circuit
ECM (PCM)
YES
Go to Step 2.
Go to Step 3.
Go to Step 4.
Go to Step 5.
Substitute a known-
good ECM (PCM)
and recheck.
NO
Go to "ENGINE
DIAG. FLOW
TABLE".
Repair or replace.
Repair or replace.
Faulty BANK-1
(BANK-2) HO2S
SENSOR-2.
Replace TWC
converter.