Infiniti M35/M45 Y50. Manual - part 648

DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-

FIRE

EC-1065

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7. 

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 

EM-191, "SPARK PLUG (PLAT-

INUM-TIPPED TYPE)"

 .

NG

>> 1. Repair or clean spark plug.

2. GO TO 8.

8. 

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 

EM-191, "SPARK

PLUG (PLATINUM-TIPPED TYPE)"

 .

9. 

CHECK COMPRESSION PRESSURE

Check compression pressure. Refer to 

EM-235, "CHECKING COMPRESSION PRESSURE"

 .

OK or NG

OK

>> GO TO 10.

NG

>> Check pistons, piston rings, valves, valve seats and cylinder head gaskets.

10. 

CHECK FUEL PRESSURE

1.

Install all removed parts.

2.

Release fuel pressure to zero. Refer to 

EC-790, "FUEL PRESSURE RELEASE"

 .

3.

Install fuel pressure gauge and check fuel pressure. Refer to 

EC-791, "FUEL PRESSURE CHECK"

 .

OK or NG

OK

>> GO TO 12.

NG

>> GO TO 11.

11. 

DETECT MALFUNCTIONING PART

Check the following.

●

Fuel pump and circuit (Refer to 

EC-1395, "FUEL PUMP"

 .)

●

Fuel pressure regulator (Refer to 

EC-791, "FUEL PRESSURE CHECK"

 .)

●

Fuel lines

●

Fuel filter for clogging

>> Repair or replace.

SEF156I

Spark should be generated.

At idling: Approximately 350 kPa (3.57 kg/cm

2

 , 51 psi)

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DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-

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12. 

CHECK IGNITION TIMING

Check the following items. Refer to 

EC-780, "Basic Inspection"

 .

OK or NG

OK

>> GO TO 13.

NG

>> Follow the 

EC-780, "Basic Inspection"

 .

Items

Specifications

Target idle speed

650 

±

 50 rpm (in P or N position)

Ignition timing

12 

±

 5

°

 BTDC (in P or N position)

DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-

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13. 

CHECK AIR FUEL RATIO (A/F) SENSOR 1 INPUT SIGNAL CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect corresponding air fuel ratio (A/F) sensor 1 harness connector.

3.

Disconnect ECM harness connector.

4.

Check harness continuity between the following terminals.
Refer to Wiring Diagram.

5.

Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.

6.

Also check harness for short to power.

OK or NG

OK

>> GO TO 14.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

: Vehicle front

1.

A/F sensor 1 (bank 2) 
harness connector

2.

A/F sensor 1 (bank 1) 
harness connector

A/F sensor 1 terminal

ECM terminal

Bank 1

1

16

2

75

5

35

6

56

Bank 2

1

76

2

77

5

57

6

58

Continuity should exist.

Bank 1

Bank 2

A/F sensor 1 terminal

ECM terminal

A/F sensor 1 terminal

ECM terminal

1

16

1

76

2

75

2

77

5

35

5

57

6

56

6

58

Continuity should not exist.

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DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-

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14. 

CHECK A/F SENSOR 1 HEATER

Refer to 

EC-889, "Component Inspection"

 .

OK or NG

OK

>> GO TO 16.

NG

>> GO TO 15.

15. 

REPLACE AIR FUEL RATIO (A/F) SENSOR 1

Replace malfunctioning A/F sensor 1.

CAUTION:

●

Discard any A/F sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a
hard surface such as a concrete floor; use a new one.

●

Before installing new A/F sensor, clean exhaust system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.

>> INSPECTION END

16. 

CHECK MASS AIR FLOW SENSOR

 With CONSULT-II

1.

Start engine and warm it up to normal operating temperature.

2.

Check mass air flow sensor signal in “DATA MONITOR” mode with CONSULT-II.

 With GST

1.

Start engine and warm it up to normal operating temperature.

2.

Check mass air flow sensor signal in Service $01 with GST.

OK or NG

OK

>> GO TO 17.

NG

>> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or

ground. Refer to 

EC-906, "DTC P0101 MAF SENSOR"

 .

17. 

CHECK SYMPTOM MATRIX CHART

Check items on the rough idle symptom in 

EC-801, "Symptom Matrix Chart"

 .

OK or NG

OK

>> GO TO 18.

NG

>> Repair or replace.

18. 

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-770, "HOW TO ERASE

EMISSION-RELATED DIAGNOSTIC INFORMATION"

 .

>> GO TO 19.

2.0 - 6.0 g·m/sec:

at idling

7.0 - 20.0 g·m/sec:

at 2,500 rpm

2.0 - 6.0 g·m/sec:

at idling

7.0 - 20.0 g·m/sec:

at 2,500 rpm