Nissan Pathfinder (2008 year). Manual - part 305

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-557

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Check “A/F ALPHA-B1”, “A/F ALPHA-B2” for approximately 1 minute because they may fluctuate. It is NG
if the indication is out of the SP value even a little.

OK or NG

OK

>> GO TO 17.

NG (Less than the SP value)>>GO TO 2.
NG (More than the SP value)>>GO TO 3.

2.

CHECK “B/FUEL SCHDL”

Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.

OK or NG

OK

>> GO TO 4.

NG (More than the SP value)>>GO TO 19.

3.

CHECK “B/FUEL SCHDL”

Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.

OK or NG

OK

>> GO TO 6.

NG (More than the SP value)>>GO TO 6.
NG (Less than the SP value)>>GO TO 25.

4.

CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

1.

Stop the engine.

2.

Disconnect PCV hose, and then plug it.

3.

Start engine.

4.

Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.

OK or NG

OK

>> GO TO 5.

NG

>> GO TO 6.

5.

CHANGE ENGINE OIL

1.

Stop the engine.

2.

Change engine oil.
NOTE:
This symptom may occur when a large amount of gasoline is mixed with engine oil because of driving
conditions (such as when engine oil temperature does not rise enough since a journey distance is too
short during winter). The symptom will not be detected after changing engine oil or changing driving con-
dition.

>> INSPECTION END

6.

CHECK FUEL PRESSURE

Check fuel pressure. (Refer to 

EC-948, "Fuel Pressure Check"

.)

OK or NG

OK

>> GO TO 9.

NG (Fuel pressure is too high)>>Replace fuel pressure regulator, refer to 

EC-948, "Fuel Pressure Check"

.

GO TO 8.

NG (Fuel pressure is too low)>>GO TO 7.

7.

DETECT MALFUNCTIONING PART

1.

Check the following.

-

Clogged and bent fuel hose and fuel tube

-

Clogged fuel filter

-

Fuel pump and its circuit (Refer to 

EC-867

.)

2.

If NG, repair or replace the malfunctioning part. (Refer to 

EC-948, "Fuel Pressure Check"

.)

If OK, replace fuel pressure regulator.

EC-558

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TROUBLE DIAGNOSIS - SPECIFICATION VALUE

>> GO TO 8.

8.

CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

1.

Start engine.

2.

Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 9.

9.

PERFORM POWER BALANCE TEST

1.

Perform “POWER BALANCE” in “ACTIVE TEST” mode.

2.

Make sure that the each cylinder produces a momentary engine speed drop.

OK or NG

OK

>> GO TO 12.

NG

>> GO TO 10.

10.

DETECT MALFUNCTIONING PART

1.

Check the following.

-

Ignition coil and its circuit (Refer to 

EC-870

.)

-

Fuel injector and its circuit (Refer to 

EC-864

.)

-

Intake air leakage

-

Low compression pressure (Refer to 

EM-163, "Compression Pressure"

.)

2.

If NG, repair or replace the malfunctioning part.
If OK, replace fuel injector. (It may be caused by leakage from fuel injector or clogging.)

>> GO TO 11.

11.

CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

1.

Start engine.

2.

Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 12.

12.

CHECK A/F SENSOR 1 FUNCTION

Perform all DTC Confirmation Procedure related with A/F sensor 1.
• For DTC P0130, P0150, refer to 

EC-615, "DTC Confirmation Procedure"

.

• For DTC P0131, P0151, refer to 

EC-619, "DTC Confirmation Procedure"

.

• For DTC P0132, P0152, refer to 

EC-623, "DTC Confirmation Procedure"

.

• For DTC P0133, P0153, refer to 

EC-627, "DTC Confirmation Procedure"

.

• For DTC P2A00, P2A03, refer to 

EC-849, "DTC Confirmation Procedure"

.

OK or NG

OK

>> GO TO 15.

NG

>> GO TO 13.

13.

CHECK A/F SENSOR 1 CIRCUIT

Perform Diagnostic Procedure according to corresponding DTC.

>> GO TO 14.

14.

CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

1.

Start engine.

2.

Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.

OK or NG

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-559

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OK

>> INSPECTION END

NG

>> GO TO 15.

15.

DISCONNECT AND RECONNECT ECM HARNESS CONNECTOR

1.

Stop the engine.

2.

Disconnect ECM harness connector. Check pin terminal and connector for damage, and then reconnect it.

>> GO TO 16.

16.

CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

1.

Start engine.

2.

Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.

OK or NG

OK

>> INSPECTION END

NG

>> Detect malfunctioning part according to 

EC-937, "Symptom Matrix Chart"

.

17.

CHECK “B/FUEL SCHDL”

Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.
OK or NG

OK

>> INSPECTION END

NG (More than the SP value)>>GO TO 18.
NG (Less than the SP value)>>GO TO 25.

18.

DETECT MALFUNCTIONING PART

1.

Check for the cause of large engine friction. Refer to the following.

-

Engine oil level is too high

-

Engine oil viscosity

-

Belt tension of power steering, alternator, A/C compressor, etc. is excessive

-

Noise from engine

-

Noise from transmission, etc.

2.

Check for the cause of insufficient combustion. Refer to the following.

-

Valve clearance malfunction

-

Intake valve timing control function malfunction

-

Camshaft sprocket installation malfunction, etc.

>> Repair or replace malfunctioning part, and then GO TO 30.

19.

CHECK INTAKE SYSTEM

Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
• Crushed air ducts
• Malfunctioning seal of air cleaner element
• Uneven dirt of air cleaner element
• Improper specification of intake air system

OK or NG

OK

>> GO TO 21.

NG

>> Repair or replace malfunctioning part, and then GO TO 20.

20.

CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”, AND “B/FUEL SCHDL”

Select “A/F ALPHA-B1”, “A/F ALPHA-B2”, and “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and
make sure that the each indication is within the SP value.

OK or NG

OK

>> INSPECTION END

NG (“B/FUEL SCHDL” is more, “A/F ALPHA-B1”, “A/F ALPHA-B2” are less than the SP value)>>GO TO 21.

21.

DISCONNECT AND RECONNECT MASS AIR FLOW SENSOR HARNESS CONNECTOR

1.

Stop the engine.

EC-560

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TROUBLE DIAGNOSIS - SPECIFICATION VALUE

2.

Disconnect mass air flow sensor harness connector. Check pin terminal and connector for damage and
then reconnect it again.

>> GO TO 22.

22.

CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

1.

Start engine.

2.

Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that the
each indication is within the SP value.

OK or NG

OK

>> 1.

Detect malfunctioning part of mass air flow sensor circuit and repair it. Refer to 

EC-591

.

2.

GO TO 29.

NG

>> GO TO 23.

23.

CHECK “MAS A/F SE-B1”

Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.

OK or NG

OK

>> GO TO 24.

NG (More than the SP value)>>Replace mass air flow sensor, and then GO TO 29.

24.

REPLACE ECM

1.

Replace ECM.

2.

Perform initialization of NVIS(NATS) system and registration of all NVIS(NATS) ignition key IDs. Refer to

SEC-8, "ECM RE-COMMUNICATING FUNCTION : Special Repair Requirement"

.

3.

Perform 

EC-496, "VIN Registration"

.

4.

Perform 

EC-497, "Accelerator Pedal Released Position Learning"

.

5.

Perform 

EC-497, "Throttle Valve Closed Position Learning"

.

6.

Perform 

EC-497, "Idle Air Volume Learning"

.

>> GO TO 29.

25.

CHECK INTAKE SYSTEM

Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
• Crushed air ducts
• Malfunctioning seal of air cleaner element
• Uneven dirt of air cleaner element
• Improper specification of intake air system

OK or NG

OK

>> GO TO 27.

NG

>> Repair or replace malfunctioning part, and then GO TO 26.

26.

CHECK “B/FUEL SCHDL”

Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.

OK or NG

OK

>> INSPECTION END

NG (Less than the SP value)>>GO TO 27.

27.

CHECK “MAS A/F SE-B1”

Select “MAS A/F SE-B1” in “SPEC” of “DATA MONITOR” mode, and make sure that the indication is within the
SP value.

OK or NG

OK

>> GO TO 28.

NG (Less than the SP value)>>Replace mass air flow sensor, and then GO TO 30.

28.

CHECK INTAKE SYSTEM

Check for the cause of air leak after the mass air flow sensor. Refer to the following.

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-561

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• Disconnection, looseness, and cracks in air duct
• Looseness of oil filler cap
• Disconnection of oil level gauge
• Open stuck, breakage, hose disconnection, or cracks of PCV valve
• Disconnection or cracks of EVAP purge hose, open stuck of EVAP canister purge volume control solenoid

valve

• Malfunctioning seal of rocker cover gasket
• Disconnection, looseness, or cracks of hoses, such as vacuum hose, connecting to intake air system parts
• Malfunctioning seal of intake air system, etc.

>> GO TO 30.

29.

CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”, AND “B/FUEL SCHDL”

Select “A/F ALPHA-B1”, “A/F ALPHA-B2”, and “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and
make sure that the each indication is within the SP value. 
OK or NG

OK

>> INSPECTION END

NG

>> Detect malfunctioning part according to 

EC-937, "Symptom Matrix Chart"

.

30.

CHECK “B/FUEL SCHDL”

Select “B/FUEL SCHDL” in “SPEC” of “DATA MONITOR” mode, and then make sure that the indication is
within the SP value.
OK or NG

OK

>> INSPECTION END

NG

>> Detect malfunctioning part according to 

EC-937, "Symptom Matrix Chart"

.

EC-562

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POWER SUPPLY AND GROUND CIRCUIT

POWER SUPPLY AND GROUND CIRCUIT

Diagnosis Procedure

INFOID:0000000001537625

1.

INSPECTION START

Start engine.
Is engine running?

Yes or No

Yes

>> GO TO 8.

No

>> GO TO 2.

2.

CHECK ECM POWER SUPPLY CIRCUIT-I

1.

Turn ignition switch OFF and then ON.

2.

Check voltage between ECM terminal 109 and ground with
CONSULT-III or tester.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 3.

3.

DETECT MALFUNCTIONING PART

Check the following.
• 10A fuse
• Harness for open or short between ECM and fuse

>> Repair harness or connectors.

4.

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

2.

Loosen and retighten three ground screws on the body.
Refer to 

EC-565, "Ground Inspection"

.

OK or NG

OK

>> GO TO 5.

NG

>> Repair or replace ground connections.

5.

CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I

1.

Disconnect ECM harness connector.

2.

Check harness continuity between ECM terminals 1, 115, 116 and ground.
Refer to Wiring Diagram.

3.

Also check harness for short to power.

Voltage: Battery voltage

MBIB0015E

BBIA0539E

Continuity should exist.

POWER SUPPLY AND GROUND CIRCUIT

EC-563

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OK or NG

OK

>> GO TO 7.

NG

>> GO TO 6.

6.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors F32, E2
• Harness for open or short between ECM and ground

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

7.

CHECK ECM POWER SUPPLY CIRCUIT-II

1.

Reconnect ECM harness connector.

2.

Turn ignition switch ON.

3.

Check voltage between IPDM E/R terminal 3 and ground with
CONSULT-III or tester.

OK or NG

OK

>> Go to 

EC-870

.

NG

>> GO TO 8.

8.

CHECK ECM POWER SUPPLY CIRCUIT-III

1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Turn ignition switch ON and then OFF.

3.

Check voltage between ECM terminals 119, 120 and ground
with CONSULT-III or tester.

OK or NG

OK

>> GO TO 13.

NG (Battery voltage does not exist.)>>GO TO 9.
NG (Battery voltage exists for more than a few seconds.)>>GO  TO

11.

9.

CHECK ECM POWER SUPPLY CIRCUIT-IV

1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Check voltage between ECM terminal 111 and ground with
CONSULT-III or tester.

OK or NG

OK

>> GO TO 10.

NG

>> GO TO 11.

10.

CHECK ECM POWER SUPPLY CIRCUIT-V

1.

Disconnect ECM harness connector.

2.

Disconnect IPDM E/R harness connector E119.

3.

Check harness continuity between ECM terminals 119, 120 and IPDM E/R terminal 4.

Voltage: Battery voltage

PBIB2569E

Voltage:

After turning ignition switch OFF, battery 
voltage will exist for a few seconds, then drop 
approximately 0V.

PBIB1630E

Voltage: Battery voltage

PBIB1191E

EC-564

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POWER SUPPLY AND GROUND CIRCUIT

Refer to Wiring Diagram.

4.

Also check harness for short to ground and short to power.

OK or NG

OK

>> GO TO 13.

NG

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

11.

CHECK ECM POWER SUPPLY CIRCUIT-VI

1.

Disconnect ECM harness connector.

2.

Disconnect IPDM E/R harness connector E119.

3.

Check harness continuity between ECM terminal 111 and IPDM E/R terminal 7.
 Refer to Wiring Diagram.

4.

Also check harness for short to ground and 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.

12.

CHECK 20A FUSE

Check 20A fuse (No. 53, located in IPDM E/R).

OK or NG

OK

>> GO TO 16.

NG

>> Replace 20A fuse.

13.

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

2.

 Loosen and retighten three ground screws on the body.
Refer to 

EC-565, "Ground Inspection"

.

OK or NG

OK

>> GO TO 14.

NG

>> Repair or replace ground connections.

14.

CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-II

1.

Disconnect ECM harness connector.

2.

Check harness continuity between ECM terminals 1, 115, 116 and ground.
Refer to Wiring Diagram.

3.

Also check harness for short to power.

OK or NG

OK

>> GO TO 16.

NG

>> GO TO 15.

15.

DETECT MALFUNCTIONING PART

 Check the following.

Continuity should exist.

Continuity should exist.

BBIA0539E

Continuity should exist.