Suzuki 2000 Grand Vitara SQ416, Service Manual

Page: 166 / 729

YH4
GRAND
VITARA
ENGINE (H25 ENGINE) 6-1-55
Fig. for STEP 3 Fig. for STEP 6
D
Intake air temperature: between – 14
_
C and 70
_
C (68
_
F and 158
_
F)
D
Atmospheric pressure: higher than 560 mmHg (Altitude: lower than 2790 m (9150 ft))
(1) With ignition switch OFF, connect scan tool.
(2) Turn ON ignition switch, clear DTC if any.
(3) Start engine and run it for 10 sec.
(4) Check 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 Check IAT Sensor and Its Circuit.
1) Connect scan tool to DLC with ignition switch OFF.
2) Turn ignition switch ON.
3) Check intake air temp. displayed on scan tool.
Is – 40
_
C (– 40
_
F) or 205
_
C (401
_
F) indicated?
Go to Step 3. Intermittent trouble.
Check for intermittent
referring to
“Intermittent and
Poor Connection” in
Section 0A.
3 Check Wire Harness.
1) Disconnect IAT sensor connector (1) with ignition
switch OFF.
2) Check for proper connection to IAT sensor at “LBl”
and “Gr / Y” wire terminals.
3) If OK, then with ignition switch ON, is voltage
applied to “LBl” wire terminal about 4.5 – 5.5 V?
Go to Step 5. “LBl” wire open or
shorted to power, or
poor C51-3-8
connection.
If wire and
connection are OK,
substitute a known-
good ECM and
recheck.
4 Does scan tool indicate – 40
_
C (– 40
_
F) at Step 2. Go to Step 6. Go to Step 5.
5 Check Wire Harness
1) Check intake air temp. displayed on scan tool with
ignition switch ON.
Is – 40
_
C (– 40
_
F) indicated?
Replace IAT sensor. “LBl” wire shorted to
ground.
If wire is OK,
substitute a known-
good ECM and
recheck.
6 Check Wire Harness.
1) Using service wire (2), connect IAT sensor
connector terminals.
2) Check intake air temp. displayed on scan tool with
ignition switch ON.
Is 205
_
C (401
_
F) indicated?
Replace IAT sensor. “LBl” wire open or
poor C51-3-21
connection.
If wire and
connection are OK,
substitute a known-
good ECM and
recheck.