Suzuki WagonR+ RB310, Service Manual

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6-6 ENGINE DIAGNOSIS
ENGINE DIAGNOSIS
GENERAL DESCRIPTION
This vehicle is equipped with an engine and emission control system which are under control of ECM.
The engine and emission control system in this vehicle are controlled by ECM. ECM has an On-Board Diagnostic
system which detects a malfunction in this system and abnormality of those parts that influence the engine exhaust
emission. When diagnosing engine troubles, be sure to have full understanding of the outline of
“ On-Board Diag-
nostic System ” and each item in “ Precaution in Diagnosing Trouble ” and execute diagnosis according to “ ENGINE
DIAGNOSTIC FLOW TABLE ” .
There is a close relationship between the engine mechanical, engine cooling system, ignition system, exhaust sys-
tem, etc. and the engine and emission control system in their structure and operation. In case of an engine trouble,
even when the malfunction indicator lamp (MIL) doesn
’ t turn ON, it should be diagnosed according to this flow table.
ON-BOARD DIAGNOSTIC SYSTEM
(VEHICLE WITH EGR VALVE)
ECM in this vehicle has following functions.
!
When the ignition switch is turned ON with the engine at a stop,
malfunction indicator lamp (MIL) (1) turns ON to check the bulb
of the malfunction indicator lamp (1).
!
When ECM detects a malfunction which gives an adverse effect
to vehicle emission while the engine is running, it makes the mal-
function indicator lamp (1) in the meter cluster of the instrument
panel turn ON or flash (flashing only when detecting a misfire
which can cause damage to the catalyst) and stores the malfunc-
tion area in its memory.
(If it detects that continuously 3 driving cycles are normal after de-
tecting a malfunction, however, it makes MIL (1) turn OFF al-
though DTC stored in its memory will remain.)
!
As a condition for detecting a malfunction in some areas in the
system being monitored by ECM and turning ON the malfunction
indicator lamp (1) due to that malfunction, 2 driving cycle detec-
tion logic is adopted to prevent erroneous detection.
!
When a malfunction is detected, engine and driving conditions
then are stored in ECM memory as freeze frame data. (For the
details, refer to description on Freeze frame data.)
!
It is possible to communicate by using not only SUZUKI scan tool
(Tech-1) (2) but also generic scan tool. (Diagnostic information
can be accessed by using a scan tool.)