Suzuki 2000 Grand Vitara SQ416, Service Manual

Page: 174 / 729

YH4
GRAND
VITARA
ENGINE (H25 ENGINE) 6-1-63
NOTE:
Check to make sure that following conditions are satisfied when using this DTC CONFIRMATION PROCE-
DURE.
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 DTC is not detected: P0135
(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 till engine speed is reached 2000 – 3000 r / min.
(5) Keep above vehicle speed for 1 min. (Throttle valve operating is kept constant in this step.)
(6) Stop vehicle and check DTC and pending DTC by using scan tool.
DTC TROUBLESHOOTING
STEP ACTION YES NO
1 Was “ENGINE DIAG. FLOW TABLE” performed? Go to Step 2. Go to “ENGINE
DIAG. FLOW
TABLE”.
2 HO2S Voltage check:
(1) With ignition switch OFF, install scan tool.
(2) Operate engine for 60 sec or more with following
condition.
Engine coolant temp > 70
_
C
Intermittent trouble.
If OK, substitute a
known-good ECM
(PCM) and recheck. Go to Step 3.
Engine coolant tem . > 70 C
Engine speed > 2000 r / min.
(3) While repeating racing engine, check “O2S B1 S1”
(HO2S voltage) displayed on scan tool.
Is less than 0.4 V voltage displayed?
3 HO2S Voltage check:
(1) Remove ECM (PCM) cover.
(2) Start engine and check voltage between C51-3-4
and C51-3-21 while repeating racing engine.
Is the voltage while fuel is cut less than 0.1 V?
Substitute a known-
good ECM (PCM)
and recheck. Go to Step 4.
4 HO2S Wire Harness check:
(1) Check “R” and “Gr / Y” wire.
Are they in good condition? Go to Step 5. Repair or replace.
5 Fuel Injector Circuit check:
(1) Check fuel injector circuit referring to “TABLE B-2”
in this section.
Is it in good condition?
Go to Step 6. Repair or replace.
6 Fuel Injector inspection:
(1) Inspect fuel injectors (No.1, 3, 5) referring to
“ENGINE AND EMISSION CONTROL” section.
Are they in good condition?
Go to Step 7. Faulty fuel injector(s).
7 Fuel Pressure inspection:
(1) Check fuel pressure referring to following
“TABLE B-3” in this section.
Is fuel pressure within specification?
Replace HO2S and
recheck.
If DTC P0131
detected, substitute a
known-good ECM
(PCM) and recheck. Repair or replace.