2005 INFINITI FX35 vq35de

DTC P0300 - P0306 MULTIPLE CYLINDER MISFIRE, NO. 1 - 6 CYLINDER MIS- FIRE
EC-285
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Revision: 2005 July 2005 FX
DTC P0300 - P0306 MULTIPLE CYLINDER MISFIRE, NO. 1 - 6 CYLINDER MIS-
FIRE
PFP:00000
On Board Diagnosis LogicABS006PS
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 1st 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.
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.
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
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.
DTC Confirmation ProcedureABS0095P
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

Signal plate

Air fuel ratio (A/F) 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.
P0305
0305 No. 5 cylinder misfire
detected No. 5 cylinder misfires.
P0306
0306 No. 6 cylinder misfire
detected No. 6 cylinder misfires.

EC-286
[VQ35DE]
DTC P0300 - P0306 MULTIPLE CYLINDER MISFIRE, NO. 1 - 6 CYLINDER MIS- FIRE
Revision: 2005 July 2005 FX
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-286, "
Diagnostic Procedure"
.
NOTE:
If 1st trip DTC is not detected during above procedure, performing
the following procedure is advised.
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 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 condi-
tions should be satisfied at the same time.
The time to driving varies according to the engine speed in the freeze frame data.
Refer to the following table.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnostic ProcedureABS006PU
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 (With CONSULT-II)>>GO TO 3.
OK (Without CONSULT-II)>>GO TO 4.
NG >> Repair or replace it.
PBIB0164E
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Engine coolant temperature
(T) condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
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).
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

DTC P0300 - P0306 MULTIPLE CYLINDER MISFIRE, NO. 1 - 6 CYLINDER MIS- FIRE
EC-287
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Revision: 2005 July 2005 FX
3. PERFORM POWER BALANCE TEST
With CONSULT-II
1. Perform “POWER BALANCE” in “ACTIVE TEST” mode.
2. Is there any cylinder which does not produce a momentary engine speed drop?
Ye s o r N o
Ye s > > G O T O 4 .
No >> GO TO 10.
PBIB0133E

EC-288
[VQ35DE]
DTC P0300 - P0306 MULTIPLE CYLINDER MISFIRE, NO. 1 - 6 CYLINDER MIS- FIRE
Revision: 2005 July 2005 FX
4. CHECK FUNCTION OF INJECTOR-I
Without CONSULT-II
1. Stop engine.
2. Disconnect harness connectors F50, F251
3. Turn ignition switch ON.
4. Check voltage between harness connector F50 terminal 5 and ground with CONSULT-II or tester.
5. Turn ignition switch OFF.
6. Disconnect ECM harness connector.
7. Check harness continuity between harness connector F50 and ECM as follows.
Refer to Wiring Diagram.
8. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> Perform trouble diagnosis for INJECTOR CIRCUIT, refer to EC-661, "
INJECTOR CIRCUIT" .
PBIB2624E
Voltage: Battery voltage
Cylinder Harness connector F50
terminal ECM terminal
1623
2442
3222
4341
5121
6740
Continuity should exist.
PBIB2323E

DTC P0300 - P0306 MULTIPLE CYLINDER MISFIRE, NO. 1 - 6 CYLINDER MIS- FIRE
EC-289
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Revision: 2005 July 2005 FX
5. CHECK FUNCTION OF INJECTOR-II
Provide battery voltage between harness connector F251 as follows
and then interrupt it. Listen to each injector operating sound.
OK or NG
OK >> GO TO 6.
NG >> Perform trouble diagnosis for INJECTOR CIRCUIT, refer to EC-661, "
INJECTOR CIRCUIT" .
Cylinder Harness connector F251 terminal
(+) (–)
156
254
352
453
551
657
Operating sound should exist.
PBIB2497E

EC-290
[VQ35DE]
DTC P0300 - P0306 MULTIPLE CYLINDER MISFIRE, NO. 1 - 6 CYLINDER MIS- FIRE
Revision: 2005 July 2005 FX
6. CHECK FUNCTION OF IGNITION COIL-I
CAUTION:
Do the following procedure in the place where ventilation is good without the combustible.
1. Turn ignition switch OFF.
2. Reconnect all harness connectors disconnected.
3. Remove fuel pump fuse in IPDM E/R to release fuel pressure. NOTE:
Do not use CONSULT-II to release fuel pressure, or fuel pres-
sure applies again during the following procedure.
4. Start engine.
5. After engine stalls, crank it 2 or 3 times to release all fuel pres- sure.
6. Turn ignition switch OFF.
7. Remove all ignition coil harness connectors to avoid the electri- cal discharge from the ignition coils.
8. Remove ignition coil and spark plug of the cylinder to be checked.
9. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
10. Connect spark plug and harness connector to ignition coil.
11. Fix ignition coil using a rope etc. with gap of 13 - 17 mm between the edge of the spark plug and grounded metal portion
as shown in the figure.
12. Crank engine for about three seconds, and check whether spark is generated between the spark plug and the grounded metal
portion.
CAUTION:

Do not approach to the spark plug and the ignition coil
within 50cm. Be careful not to get an electrical shock
while checking, because the electrical discharge voltage
becomes 20kV or more.

It might cause to damage the ignition coil if the gap of 17 mm or more is taken.
NOTE:
When the gap is 13 mm or less, the spark might be generated even if the coil is malfunctioning.
OK or NG
OK >> GO TO 10.
NG >> GO TO 7.
7. CHECK FUNCTION OF IGNITION COIL-II
1. Turn ignition switch OFF.
2. Disconnect spark plug and connect a known-good spark plug.
3. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.
OK or NG
OK >> GO TO 8.
NG >> Check ignition coil, power transistor and their circuits. Refer to EC-648, "
IGNITION SIGNAL" .
Spark should be generated.
PBIB1603E
PBIB2325E
Spark should be generated.

DTC P0300 - P0306 MULTIPLE CYLINDER MISFIRE, NO. 1 - 6 CYLINDER MIS- FIRE
EC-291
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Revision: 2005 July 2005 FX
8. CHECK SPARK PLUG
Check the initial spark plug for fouling, etc.
OK or NG
OK >> Replace spark plug(s) with standard type one(s). For spark plug type, refer to MA-20, "
Changing Spark Plugs
(Platinum-Tipped Type)" .
NG >> 1. Repair or clean spark plug.
2. GO TO 9.
9. CHECK FUNCTION OF IGNITION COIL-III
1. Reconnect the initial spark plugs.
2. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and the grounded portion.
OK or NG
OK >> INSPECTION END
NG >> Replace spark plug(s) with standard type one(s). For spark plug type, refer to MA-20, "
Changing
Spark Plugs (Platinum-Tipped Type)" .
10. CHECK COMPRESSION PRESSURE
Check compression pressure. Refer to EM-100, "
CHECKING COMPRESSION PRESSURE" .
OK or NG
OK >> GO TO 11.
NG >> Check pistons, piston rings, valves, valve seats and cylinder head gaskets.
11 . CHECK FUEL PRESSURE
1. Install all removed parts.
2. Release fuel pressure to zero. Refer to EC-99, "
FUEL PRESSURE RELEASE" .
3. Install fuel pressure gauge and check fuel pressure. Refer to EC-99, "
FUEL PRESSURE CHECK" .
OK or NG
OK >> GO TO 13.
NG >> GO TO 12.
SEF156I
Spark should be generated.
Standard: 1,275 kPa (13.0 kg/cm
2 , 185 psi)/300 rpm
Minimum: 981 kPa (10.0 kg/cm
2 , 142 psi)/300 rpm
Difference between each
cylinder: 98 kPa (1.0 kg/cm
2 , 14 psi)/300 rpm
At idle: Approximately 350 kPa (3.57 kg/cm
2 , 51 psi)

EC-292
[VQ35DE]
DTC P0300 - P0306 MULTIPLE CYLINDER MISFIRE, NO. 1 - 6 CYLINDER MIS- FIRE
Revision: 2005 July 2005 FX
12. DETECT MALFUNCTIONING PART
Check the following.

Fuel pump and circuit (Refer to EC-668, "FUEL PUMP CIRCUIT" .)

Fuel pressure regulator (Refer to EC-99, "FUEL PRESSURE CHECK" .)

Fuel lines (Refer to MA-17, "Checking Fuel Lines" .)

Fuel filter for clogging
>> Repair or replace.
13. CHECK IGNITION TIMING
Check the following items. Refer to EC-78, "
Basic Inspection" .
OK or NG
OK >> GO TO 14.
NG >> Follow the EC-78, "
Basic Inspection" .
Items Specifications
Target idle speed 650 ± 50 rpm (in P or N position)
Ignition timing 15 ± 5 ° BTDC (in P or N position)