Dtc P0300 Random Misfire Detected; Dtc P0301 Cylinder 1 Misfire Detected; Dtc P0302 Cylinder 2 Misfire Detected; Dtc P0303 Cylinder 3 Misfire Detected - Suzuki 2000 Grand Vitara SQ625 Service Manual

6-1-88 ENGINE (H25 ENGINE)

DTC P0300 RANDOM MISFIRE DETECTED

DTC P0301 CYLINDER 1 MISFIRE DETECTED

DTC P0302 CYLINDER 2 MISFIRE DETECTED

DTC P0303 CYLINDER 3 MISFIRE DETECTED

DTC P0304 CYLINDER 4 MISFIRE DETECTED

DTC P0305 CYLINDER 5 MISFIRE DETECTED

DTC P0306 CYLINDER 6 MISFIRE DETECTED

SYSTEM DESCRIPTION
ECM (PCM) 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 (PCM) 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 DETECTING CONDITION
P0300
Misfire, which causes catalyst to overheat during 200 engine
revolutions, is detected at 2 or more cylinders. (MIL flashes as
long as this misfire occurs continuously.)
Misfire, which affects exhaust emission adversely during 1000
engine revolution, is detected at 2 or more cylinders.
P0301, P0302, P0303, P0304, P0305, P0306
Misfire, which causes catalyst to overheat during 200 engine
revolutions, is detected at 1 cylinder. (MIL flashes as long as this
misfire occurs continuously.)
Misfire, which affects exhaust emission adversely during 1000
engine revolution, is detected at 1 cylinder.
DTC CONFIRMATION PROCEDURE
NOTE:
Check to make sure that following conditions are satisfied when using this DTC CONFIRMATION PROCE-
DURE.
WARNING:
D When performing a road test, select a place where there is no traffic or possibility of a traffic accident
and very careful during to avoid occurrence of an accident.
D Road test, should be carried out with 2 person, a driver and tester, on a level road.
D Intake air temperature: between –14 C and 70 C (6.8 F and 158 F)
D Atmospheric pressure: higher than 560 mmHg (Altitude: lower than 2790 m (9150 ft))
D Following DTCs are not detected: P0335 and P0340 (No.42)
(1) With ignition switch OFF, connect scan tool.
(2) Turn ON ignition switch and clear DTC by using scan tool if any.
(3) Operate vehicle within freeze frame data condition as noted for 1 min.
(4) Stop vehicle and check DTC and pending DTC by using scan tool.
TROUBLE AREA
Ignition system
Fuel injector and its circuit
Fuel pressure
EGR system
Fuel level sensor
Abnormal air drawn in
Engine compression
Valve lash adjuster
Valve timing