DTC P0300 - P0306 MULTIPLE CYLINDER MISFIRE, NO.

1 - 6 CYLINDER MIS-
FIRE

DTC P0300 - P0306 MULTIPLE CYLINDER MISFIRE, NO. 1 - 6 CYLINDER MIS-

FIRE PFP:00000 A

On Board Diagnosis Logic UBS0095C

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crank- EC
shaft position (CKP) sensor (POS) signal to vary, ECM can determine that a misfire is occurring.
Sensor Input Signal to ECM ECM function
Crankshaft position sensor (POS) Engine speed On board diagnosis of misfire C

The misfire detection logic consists of the following two conditions.

1. One Trip Detection Logic (Three Way Catalyst Damage) D
On the first trip that a misfire condition occurs that can damage the three way catalyst (TWC) due to over-
heating, the MIL will blink.
When a misfire condition occurs, the ECM monitors the CKP sensor signal every 200 engine revolutions
for a change. E
When the misfire condition decreases to a level that will not damage the TWC, the MIL will turn off.
If another misfire condition occurs that can damage the TWC on a second trip, the MIL will blink.
When the misfire condition decreases to a level that will not damage the TWC, the MIL will remain on. F
If another misfire condition occurs that can damage the TWC, the MIL 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 MIL will only G
light when the misfire is detected on a second trip. During this condition, the ECM monitors the CKP sen-
sor signal every 1,000 engine revolutions.
A misfire malfunction can be detected on any one cylinder or on multiple cylinders.
H
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0300 Multiple cylinder misfire ● Improper spark plug
Multiple cylinder misfire. I
0300 detected ● Insufficient compression
P0301 No.1 cylinder misfire ● Incorrect fuel pressure
No. 1 cylinder misfires.
0301 detected ● The injector circuit is open or shorted
P0302 No. 2 cylinder misfire J
No. 2 cylinder misfires. ● Fuel injectors
0302 detected
● Intake air leak
P0303 No. 3 cylinder misfire ● The ignition signal circuit is open or
No. 3 cylinder misfires.
0303 detected shorted K
P0304 No. 4 cylinder misfire ● Lack of fuel
No. 4 cylinder misfires.
0304 detected ● Signal plate
P0305 No. 5 cylinder misfire ● Air fuel ratio (A/F) sensor 1 L
No. 5 cylinder misfires.
0305 detected
● Incorrect PCV hose connection
P0306 No. 6 cylinder misfire
No. 6 cylinder misfires.
0306 detected M
DTC Confirmation Procedure UBS0095D

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.

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WITH CONSULT-II
1. Turn ignition switch ON, and select “DATA MONITOR” mode
with CONSULT-II.
2. Start engine and warm it up to normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Restart engine and let it idle for about 15 minutes.
5. If 1st trip DTC is detected, go to EC-264, "Diagnostic Procedure"
.
NOTE:
If 1st trip DTC is not detected during above procedure, performing
the following procedure is advised. PBIB0164E

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Start engine and drive the vehicle under the similar conditions to (1st trip) Freeze Frame Data for a certain
time. Refer to the table below.
Hold the accelerator pedal as steady as possible.

The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following con-
ditions should be satisfied at the same time.
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the feeze frame data ± 10 km/h (5 MPH)
When the freeze frame data shows lower than 70 °C (158 °F),
Engine coolant temperature T should be lower than 70 °C (158 °F).
(T) condition When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).

The time to driving varies according to the engine speed in the freeze frame data.
Engine speed Time
Around 1,000 rpm Approximately 10 minutes
Around 2,000 rpm Approximately 5 minutes
More than 3,000 rpm Approximately 3.5 minutes

WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnostic Procedure UBS0095E

1. CHECK FOR INTAKE AIR LEAK AND PCV HOSE

1. Start engine and run it at idle speed.
2. Listen for the sound of the intake air leak.
3. Check PCV hose connection.
OK or NG
OK >> GO TO 2.
NG >> Discover air leak location and repair.

2. CHECK FOR EXHAUST SYSTEM CLOGGING

Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace it.

Revision: June 2004 EC-264 2004 Maxima

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3. PERFORM POWER BALANCE TEST A

With CONSULT-II
1. Perform “POWER BALANCE” in “ACTIVE TEST” mode.
EC
2. Is there any cylinder which does not produce a momentary
engine speed drop?

PBIB0133E
E
Without CONSULT-II
When disconnecting each injector harness connector one at a time,
is there any cylinder which does not produce a momentary engine F
speed drop?
Yes or No
Yes >> GO TO 4. G
No >> GO TO 7.

BBIA0237E

I
4. CHECK INJECTOR
Does each injector make an operating sound at idle?
J
Yes or No
Yes >> GO TO 5.
No >> Check injector(s) and circuit(s). Refer to EC-649,
K
"INJECTOR CIRCUIT" .

MEC703B
M

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5. CHECK IGNITION SPARK

1. Remove ignition coil assembly from rocker cover.
2. Remove spark plug from ignition coil assembly
3. Connect a known good spark plug to the ignition coil.
4. Place end of spark plug against a suitable ground and crank engine.
5. Check for spark.
OK or NG
OK >> GO TO 6.
NG >> Check ignition coil, power transistor and their circuits.
Refer to EC-629, "IGNITION SIGNAL" .

SEF575Q

6. CHECK SPARK PLUGS

Remove the spark plugs and check for fouling, etc.
OK or NG
OK >> GO TO 7.
NG >> Repair or replace spark plug(s) with standard type
one(s). For spark plug type, refer to, MA-18, "Changing
Spark Plugs (Platinum - Tipped Type)" .

SEF156I

7. CHECK COMPRESSION PRESSURE

Check compression pressure. Refer to EM-99, "CHECKING COMPRESSION PRESSURE" .
OK or NG
OK >> GO TO 8.
NG >> Check pistons, piston rings, valves, valve seats and cylinder head gaskets.

8. CHECK FUEL PRESSURE

1. Install all removed parts.
2. Release fuel pressure to zero. Refer to EC-51, "FUEL PRESSURE RELEASE" .
3. Install fuel pressure gauge and check fuel pressure. Refer to EC-51, "FUEL PRESSURE CHECK" .

At idle: Approx. 350 kPa (3.57 kg/cm2 , 51 psi)

OK or NG
OK >> GO TO 10.
NG >> GO TO 9.

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9. DETECT MALFUNCTIONING PART A

Check the following.
● Fuel pump and circuit (Refer to EC-655, "FUEL PUMP CIRCUIT" .)
● Fuel pressure regulator (Refer to EC-51, "FUEL PRESSURE CHECK" .) EC
● Fuel lines
● Fuel filter for clogging
C

>> Repair or replace.

10. CHECK IGNITION TIMING D

Check the following items. Refer to EC-85, "Basic Inspection" .

E
Items Specifications
M/T 625 ± 50 rpm
Target idle speed 4-speed A/T 700 ± 50 rpm (in P or N position) F
5-speed A/T 675 ± 50 rpm (in P or N position)
M/T 15 ± 5° BTDC
Ignition timing G
A/T 15 ± 5° BTDC (in P or N position)
OK or NG
OK >> GO TO 11. H
NG >> Follow the EC-85, "Basic Inspection" .

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11. CHECK A/F SENSOR 1 INPUT SIGNAL

1. Turn ignition switch OFF.
2. Disconnect A/F sensor 1 harness connector.

BBIA0235E

3. Disconnect ECM harness connector.

4. Check harness continuity between the following terminals.
Refer to Wiring Diagram, EC-483, "Wiring Diagram" .
Bank 1 Bank 2
ECM terminal A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal
76 1 16 1
57 5 35 5
58 6 56 6
77 2 75 2

Continuity should exist.

5. Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.
Bank 1 Bank 2
ECM terminal A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal
76 1 16 1
57 5 35 5
58 6 56 6
77 2 75 2

Continuity should not exist.

6. Also check harness for short to power.
OK or NG
OK >> GO TO 12.
NG >> Repair open circuit or short to ground or short to power in harness or connectors between ECM
and A/F sensor 1.

12. CHECK A/F SENSOR 1 HEATER

Refer to EC-405, "Component Inspection" .
OK or NG
OK >> GO TO 13.
NG >> Replace A/F sensor 1.

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13. CHECK MASS AIR FLOW SENSOR A

With CONSULT-II
Check mass air flow sensor signal in “DATA MONITOR” mode with CONSULT-II.
2.0 - 6.0 g·m/sec: at idling EC
7.0 - 20.0 g·m/sec: at 2,500 rpm
With GST C
Check mass air flow sensor signal in MODE 1 with GST.
2.0 - 6.0 g·m/sec: at idling
7.0 - 20.0 g·m/sec: at 2,500 rpm D

OK or NG
OK >> GO TO 14. E
NG >> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or
engine grounds. Refer to EC-164, "DTC P0101 MAF SENSOR" .

14. CHECK SYMPTOM MATRIX CHART F

Check items on the rough idle symptom in EC-90, "Symptom Matrix Chart" .
OK or NG G
OK >> GO TO 15.
NG >> Repair or replace.
H
15. ERASE THE 1ST TRIP DTC
Some tests may cause a 1st trip DTC to be set.
Erase the 1st trip DTC from the ECM memory after performing the tests. Refer to EC-68, "HOW TO ERASE I
EMISSION-RELATED DIAGNOSTIC INFORMATION" .

>> GO TO 16. J

16. CHECK INTERMITTENT INCIDENT

K
Refer to EC-139, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .

>> INSPECTION END L

Revision: June 2004 EC-269 2004 Maxima