Suzuki GA413 Service Manual page 421

DIAGNOSIS
The engine and emission control system in this vehicle are con-
trolled by ECM. ECM has an On-Board Diagnostic system which
detects a malfunction in this system.
When diagnosing troubles, be sure to have full understanding of
the outline of "On-Board Diagnostic System" and each item in "Pre-
caution in Diagnosing Trouble" and execute diagnosis according
to "Engine Diagnostic Flow Table" in section 6.
ON-BOARD DIAGNOSTIC SYSTEM
ECM performs on-board diagnosis (self-diagnosis) on the system
and operates "CHECK ENGINE" lamp (malfunction indicator lamp)
as follows.
D Malfunction indicator lamp ("CHECK ENGINE" light) lights when
the ignition switch is turned ON position (but the engine at stop)
regardless of the condition of Engine and emission control sys-
tem. This is only to check the malfunction indicator lamp
("CHECK ENGINE" light) bulb and its circuit.
D If the areas monitored by ECM is free from any trouble after the
engine start (while engine is running), malfunction indicator
lamp ("CHECK ENGINE" light) turns OFF.
D When ECM detects a trouble which has occurred in the areas,
it makes malfunction indicator lamp ("CHECK ENGINE" light)
turn ON while the engine is running to warn the driver of such oc-
currence of trouble and at the same time it stores the exact
trouble area in ECM back-up memory.
PRECAUTIONS IN DIAGNOSING TROUBLES
D Before identifying diagnostic trouble code, don't disconnect cou-
plers from ECM, battery cable from battery, ECM ground wire
harness from engine. Such disconnection will erase memorized
trouble in ECM memory.
D Be sure to read "Precautions for Electrical Circuit Service" in
Section 0A before inspection and observe what is written there.
D ECM replacement
When substituting a known-good ECM, check for the following
conditions. Neglecting this check may cause damage to known-
good ECM.
– Resistance value of all relays, actuators is as specified re-
spectively.
– TP sensor and MAP sensor are in good condition and none of
power circuits of these sensors is shorted to ground.
ENGINE AND EMISSION CONTROL SYSTEM 6E-11