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DTC P0300 - P0304 MULTIPLE CYLINDER MISFIRE, NO. 1 - 4 CYLINDER MIS-
FIRE
EC-237
[QR (WITH EURO-OBD)]
C
D
E
F
G
H
I
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K
L
M
A
EC
DTC P0300 - P0304 MULTIPLE CYLINDER MISFIRE, NO. 1 - 4 CYLINDER MIS-
FIRE
PFP:00000
On Board Diagnosis Logic EBS010PJ
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crank-
shaft position (CKP) sensor (POS) signal to vary, ECM can determine that a misfire is occurring.
The misfire detection logic consists of the following two conditions.
1. One Trip Detection Logic (Three Way Catalyst Damage)
On the first trip that a misfire condition occurs that can damage the three way catalyst (TWC) due to over-
heating, the MI will blink.
When a misfire condition occurs, the ECM monitors the CKP sensor (POS) signal every 200 engine revo-
lutions for a change.
When the misfire condition decreases to a level that will not damage the TWC, the MI will turn off.
If another misfire condition occurs that can damage the TWC on a second trip, the MI will blink.
When the misfire condition decreases to a level that will not damage the TWC, the MI will remain on.
If another misfire condition occurs that can damage the TWC, the MI will begin to blink again.
2. Two Trip Detection Logic (Exhaust quality deterioration)
For misfire conditions that will not damage the TWC (but will affect vehicle emissions), the MI will only light
when the misfire is detected on a second trip. During this condition, the ECM monitors the CKP sensor
signal every 1,000 engine revolutions.
A misfire malfunction can be detected on any one cylinder or on multiple cylinders.
DTC Confirmation Procedure EBS010PK
CAUTION:
Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws when driv-
ing.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
Sensor Input Signal to ECM ECM function
Crankshaft position sensor (POS) Engine speed On board diagnosis of misfire
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0300
0300
Multiple cylinder misfire
detected
Multiple cylinder misfire.
● Improper spark plug
● Insufficient compression
● Incorrect fuel pressure
● The injector circuit is open or shorted
● Fuel injector
● Intake air leak
● The ignition signal circuit is open or
shorted
● Lack of fuel
● Drive plate or flywheel
● Heated oxygen sensor 1
● Incorrect PCV hose connection
P0301
0301
No.1 cylinder misfire
detected
No. 1 cylinder misfires.
P0302
0302
No. 2 cylinder misfire
detected
No. 2 cylinder misfires.
P0303
0303
No. 3 cylinder misfire
detected
No. 3 cylinder misfires.
P0304
0304
No. 4 cylinder misfire
detected
No. 4 cylinder misfires.
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