Suzuki WagonR+ RB310, Service Manual

Page: 2430 / 3086

ENGINE DIAGNOSIS 6-71
Below
specified value
1. CKP sensor signal
2. No.1 fuel injector signal
3. No.3 fuel injector signal
4. Fuel injection time
Display of fuel injection signal using oscilloscope
Waveforms at specified idle speed
5ms/Div
DTC DETECTING CONDITION POSSIBLE CAUSE
!
Engine under other than high revolution condition
!
Not on rough road
!
Engine speed changing rate
!
Manifold absolute
pressure changing rate
!
Throttle opening changing rate
!
Misfire rate per 200 or 1000 engine revolutions (how
much and how often crankshaft revolution speed
changes) is higher than specified value
!
Engine overheating
!
Vacuum leaks (air inhaling) from air intake system
!
Ignition system malfunction (spark plug(s), high-
tension cord(s), ignition coil assembly)
!
Fuel pressure out of specification
!
Fuel injector malfunction (clogged or leakage)
!
Engine compression out of specification
!
Valve lash (clearance) out of specification
!
Manifold absolute pressure sensor malfunction
!
Engine coolant temp. sensor malfunction
!
PCV valve malfunction
!
EVAP control system malfunction
!
EGR system malfunction
DTC CONFIRMATION PROCEDURE
NOTE:
Among different types of random misfire, if misfire occurs at cylinders 1 and 4 or cylinders 3 and 2 simulta-
neously, it may not possible to reconfirm DTC by using the following DTC confirmation procedure. When
diagnosing the trouble of DTC P0300 (Random misfire detected) of the engine which is apparently misfir-
ing, even if DTC P0300 cannot be reconfirmed by using the following DTC confirmation procedure, pro-
ceed to the following Diag. Flow Table.
WARNING:
!
When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and be very careful during testing to avoid occurrence of an accident.
!
Road test should be carried out with 2 persons, a driver and a tester.
1) Turn ignition switch OFF.
2) Clear DTC with ignition switch ON.
3) Check vehicle and environmental condition for:
– Indication of fuel level meter in combination meter: 1/4 or more
– Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
– Ambient temp.: – 10
"
C, 14
"
F or higher – Intake air temp.: 70
"
C, 158
"
F or lower
– Engine coolant temp.: – 10 – 110
"
C, 14 – 230
"
F
4) Start engine and keep it at idle for 2 min. or more.
5) Check DTC in
“ DTC ” mode and pending DTC in “ ON BOARD TEST ” or “ PENDING DTC ” mode.
6) If DTC is not detected at idle, consult usual driving based on information obtained in “ Customer complaint analy-
sis ” and “ Freeze frame data check ” .
Reference