Suzuki 2000 Grand Vitara SQ416, Service Manual

Page: 13 / 729

YH4
GRAND
VITARA
or
ENGINE DIAGNOSIS (G16 / J20 ENGINES) 6-9
ON-BOARD DIAGNOSTIC SYSTEM
(VEHICLE WITHOUT MONITOR CONNECTOR)
ECM diagnosis troubles which may occur in the area including the
following parts when the ignition switch is ON and the engine is run-
ning, and indicates the result by turning on or flashing malfunction
indicator lamp (1).
Heated oxygen sensor EGR valve (if equipped)
ECT sensor CKP sensor (if equipped)
TP sensor
IAT sensor
MAP sensor
CMP sensor
MAF sensor
VSS
CPU (Central Processing Unit) of ECM
ECM and malfunction indicator lamp (1) operate as follows.
Malfunction indicator lamp (1) lights when the ignition switch is
turned ON (but the engine at stop) with the diagnosis switch termi-
nal ungrounded regardless of the condition of Engine and Emis-
sion Control system. This is only to check the malfunction indica-
tor lamp (1) bulb and its circuit.
If the above areas of Engine and Emission Control system is free
from any trouble after the engine start (while engine is running),
malfunction indicator lamp (1) turns OFF.
When ECM detects a trouble which has occurred in the above
areas, it makes malfunction indicator lamp (1) turn ON while the
engine is running to warn the driver of such occurrence of trouble
and at the same time it stores the trouble area in ECM back-up
memory. (The memory is kept as it is even if the trouble was only
temporary and disappeared immediately. And it is not erased un-
less the power to ECM is shut off for specified time below.)
ECM also indicates trouble area in memory by means of flashing
of malfunction indicator lamp (1) at the time of inspection. (i.e.
when diagnosis switch terminal (2) is grounded and ignition
switch is turned ON.)
NOTE:
When a trouble occurs in the above areas and disappears
soon while the diagnosis switch terminal is ungrounded and
the engine is running, malfunction indicator lamp (1) lights
and remains ON as long as the trouble exists but it turns OFF
when the normal condition is restored.