Suzuki 2006 SX4, Service Manual

Page: 129 / 1478

Engine General Information and Diagnosis: 1A-85
DTC P0300 / P0301 / P0302 / P0303 / P0304: Random Misfire Detected / Cylinder 1 / Cylinder 2 /
Cylinder 3 / Cylinder 4 Misfire Detected
S6RW0C1104035
System Description
ECM measure the angle of the crankshaft based on the pulse signal from the CKP sensor and CMP sensor for each
cylinder. If it detects a large change in the angle speed of the crankshaft, it concludes occurrence of a misfire. When
the number of misfire is counted by ECM beyond the DTC detecting condition, it determine the cylinder where the
misfire occurred and output it as DTC.
DTC Detecting Condition and Trouble Area
DTC Confirmation Procedure
WARNING
!
• When performing a road test, select a place where there is no traffic or possibility of a traffic
accident and very careful during testing to avoid occurrence of an accident.
• Road test should be carried out with 2 persons, a driver and a tester, on a level road.
NOTE
Check to make sure that the following conditions are satisfied when using this “DTC Confirmation
Procedure”.
• Intake air temperature at engine start: –10
°
C (14
°
F) to 80
°
C (176
°
F)
• Intake air temperature: –10
°
C (14
°
F) to 70
°
C (158
°
F)
• Engine coolant temperature: 70
°
C (158
°
F) to 150
°
C (302
°
F)
• Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg, 75 kPa or more)
• The following DTCs are not detected: DTCs related to MAF sensor, ECT sensor, IAT sensor,
barometric pressure sensor, TP sensor, CKP sensor and CMP sensor
1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and print Freeze Frame Data or write them down using scan tool.
3) Clear DTC using scan tool.
4) Drive vehicle under freeze frame data condition as noted for 1 min. or more.
5) Stop vehicle and check DTC and pending DTC.
DTC detecting condition Trouble area
P0300:
• Misfire, which causes catalyst to overheat during 200 engine revolutions, is
detected at 2 or more cylinders. (MIL blinks as long as this misfire occurs
continuously.)
• Misfire, which affects exhaust emission adversely during 1000 engine revolution, is
detected at 2 or more cylinders.
(2 driving cycle detection logic)
• Ignition system
• Fuel injector and its circuit
• Fuel pressure
• Fuel level sensor
• Abnormal air drawn in
• Engine compression
• Valve lash (clearance)
• Valve timing
• Fuel shortage
• Exhaust system
• Fuel of poor quality
P0301, P0302, P0303, P0304
• Misfire, which causes catalyst to overheat during 200 engine revolutions, is
detected at 1 cylinder. (MIL blinks as long as this misfire occurs continuously.)
• Misfire, which affects exhaust emission adversely during 1000 engine revolution, is
detected at 1 cylinder.
(2 driving cycle detection logic)