Suzuki Engine 2002 GRAND VITARA SQ625, Service Manual

Page: 713 / 834

6E2-20 ENGINE AND EMISSION CONTROL SYSTEM (H25 ENGINE)
b) Not using SUZUKI scan tool (vehicle with monitor connec-
tor)
i) Disconnect scan tool from DLC if connected.
ii) Warm up engine to normal operating temperature.
iii) Stop engine and connect duty meter (3) between duty out-
put terminal and ground terminal of diagnosis connector
(1) (white connector).
iv) Using service wire (2), ground diagnosis switch terminal in
diagnosis connector.
v) Set tachometer.
vi) Start engine and warm it up completely.
vii) Check IAC duty and idle speed. If duty and/or idle speed is
out of specifications, check idle air control system referring
to Diagnostic Flow Table B-4 “Idle Air Control System
Check” in Section 6-1.
Engine idle speed
A/C OFF : 750 ± 50 r/min.
A/C ON : 800 ± 50 r/min.
IAC duty at specified idle speed
10 – 50% (1.4 – 7.0 V when battery voltage is 14 V)
IAC duty to voltage relation
NOTE:
If ECM (PCM) parts No. ends with “0”, ECM (PCM) does
not output IAC duty through duty output terminal in mon-
itor coupler. First of all, check label on ECM (PCM) for
part No. if so, check IAC duty by using SUZUKI scan tool.
A : Output duty select switch terminal D : Ground terminal
B : Diagnosis switch terminal E : Test switch terminal
C : Blank F : Duty output terminal
NOTE:
IAC duty can be checked roughly by using voltmeter. IAC
duty to voltage relation is as follows.
• “OFF DUTY METER” is such duty meter that indicates
approx. 100% when terminal voltage is approx. “0 V”.
• “VB” represents battery voltage while engine of vehi-
cle being checked is running.
ON DUTY METER
INDICATION (%)
OFF DUTY METER
INDICATION (%)
VOLTMETER INDI-
CATION (V)
0
50
100
100
50
0
0
0.5 x V
B
V
B