Suzuki WagonR+ RB310 Service Manual page 2430

DTC DETECTING CONDITION
D Engine under other than high revolution condition
D Not on rough road
D Engine speed changing rate
D Manifold absolute
pressure changing rate
D Throttle opening changing rate
D Misfire rate per 200 or 1000 engine revolutions (how
much and how often crankshaft revolution speed
changes) is higher than specified value
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:
D 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.
D 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
– 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
Display of fuel injection signal using oscilloscope
D Engine overheating
D Vacuum leaks (air inhaling) from air intake system
D Ignition system malfunction (spark plug(s), high-
Below
tension cord(s), ignition coil assembly)
specified value
D Fuel pressure out of specification
D Fuel injector malfunction (clogged or leakage)
D Engine compression out of specification
D Valve lash (clearance) out of specification
D Manifold absolute pressure sensor malfunction
D Engine coolant temp. sensor malfunction
D PCV valve malfunction
D EVAP control system malfunction
D EGR system malfunction
– Intake air temp.: 70_C, 158_F or lower
Waveforms at specified idle speed
ENGINE DIAGNOSIS 6-71
POSSIBLE CAUSE
5ms/Div
1. CKP sensor signal
2. No.1 fuel injector signal
3. No.3 fuel injector signal
4. Fuel injection time