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Nissan Pathfinder (2011 year). Manual - part 254

EC-86

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

DTC/CIRCUIT DIAGNOSIS

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

Description

INFOID:0000000006243770

The specification (SP) value indicates the tolerance of the value that is displayed in “SPEC” of “DATA MONI-

TOR” mode of CONSULT-III during normal operation of the Engine Control System. When the value in “SPEC”

of “DATA MONITOR” mode is within the SP value, the Engine Control System is confirmed OK. When the

value “SPEC” of “DATA MONITOR” mode is NOT within the SP value, the Engine Control System may have

one or more malfunctions.

The SP value is used to detect malfunctions that may affect the Engine Control System, but will not illuminate

the MIL.

The SP value will be displayed for the following three items:

• B/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board correc-

tion)

• A/F ALPHA-B1/B2 (The mean value of air-fuel ratio feedback correction factor per cycle)

• MAS A/F SE-B1 (The signal voltage of the mass air flow sensor)

Testing Condition

INFOID:0000000006243771

• Vehicle driven distance: More than 5,000 km (3,107 miles)
• Barometric pressure: 98.3 - 104.3 kPa (1.003 - 1.064 kg/cm

, 14.25 - 15.12 psi)

• Atmospheric temperature: 20 - 30

C (68 - 86

• Engine coolant temperature: 75 - 95

C (167 - 203

• Transmission: Warmed-up*

• Electrical load: Not applied*

• Engine speed: Idle

*1: After the engine is warmed up to normal operating temperature, drive vehicle until “FLUID TEMP SE” (A/T

fluid temperature sensor signal) indicates more than 60

C (140

F).

*2: Rear window defogger switch, air conditioner switch lighting switch are OFF. Steering wheel is straight

ahead.

Inspection Procedure

INFOID:0000000006243772

NOTE:

Perform “SPEC” of “DATA MONITOR” mode in maximum scale display.
1. Perform

EC-20, "Basic Inspection"

2. Confirm that the testing conditions indicated above are met.
3. Select “B/FUEL SCHDL”, “A/F ALPHA-B1”, “A/F ALPHA-B2” and “MAS A/F SE-B1” in “SPEC” of “DATA

MONITOR” mode with CONSULT-III.

4. Make sure that monitor items are within the SP value.
5. If NG, go to

EC-86, "Diagnosis Procedure"

Diagnosis Procedure

INFOID:0000000006243773

OVERALL SEQUENCE

2011 Pathfinder

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-87

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

JMBIA1468GB

2011 Pathfinder

EC-88

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

DETAILED PROCEDURE

CHECK “A/F ALPHA-B1”, “A/F ALPHA-B2”

1. Start engine.

2. Confirm that the testing conditions are met. Refer to

EC-86, "Testing Condition"

3. Select “A/F ALPHA-B1”, “A/F ALPHA-B2” in “SPEC” of “DATA MONITOR” mode, and make sure that

each indication is within the SP value.

NOTE:

PBIB3214E

2011 Pathfinder

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-89

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

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

>> GO TO 17.

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

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

>> GO TO 4.

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

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

>> GO TO 6.

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

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

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

each indication is within the SP value.

OK or NG

>> GO TO 5.

>> GO TO 6.

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-

ditions.

INSPECTION END

CHECK FUEL PRESSURE

Check fuel pressure. (Refer to

EC-484, "Fuel Pressure Check"

OK or NG

>> GO TO 9.

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

EC-478, "Precaution"

and

FL-11,

"Removal and Installation"

. GO TO 8.

NG (Fuel pressure is too low)>>GO TO 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-403, "Description"

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

EC-86, "Diagnosis Procedure"

If OK, replace fuel pressure regulator.

2011 Pathfinder

EC-90

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

>> GO TO 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

each indication is within the SP value.

OK or NG

INSPECTION END

>> GO TO 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

>> GO TO 12.

>> GO TO 10.

10.

DETECT MALFUNCTIONING PART

1. Check the following below

Ignition coil and its circuit (Refer to

EC-407, "Component Description"

Fuel injector and its circuit (Refer to

EC-399, "Component Description"

Intake air leakage

Low compression pressure (Refer to

EM-23, "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

each indication is within the SP value.

OK or NG

INSPECTION END

>> 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-148, "DTC Confirmation Procedure"

• For DTC P0131, P0151, refer to

EC-152, "DTC Confirmation Procedure"

• For DTC P0132, P0152, refer to

EC-156, "DTC Confirmation Procedure"

• For DTC P0133, P0153, refer to

EC-160, "DTC Confirmation Procedure"

• For DTC P2A00, P2A03, refer to

EC-385, "DTC Confirmation Procedure"

OK or NG

>> GO TO 15.

>> 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

each indication is within the SP value.

2011 Pathfinder

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-91

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

OK or NG

INSPECTION END

>> 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

each indication is within the SP value.

OK or NG

INSPECTION END

>> Detect malfunctioning part according to

EC-472, "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

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

>> GO TO 21.

>> 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 each indication is within the SP value.
OK or NG

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

2011 Pathfinder

EC-92

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

1. Stop the engine.

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

each indication is within the SP value.

OK or NG

>> 1. Detect malfunctioning part of mass air flow sensor circuit and repair it. Refer to

EC-114,

"Diagnosis Procedure"

2. GO TO 29.

>> 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

>> 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-10, "ECM RE-COMMUNICATING FUNCTION : Special Repair Requirement"

(with Intelligent Key

system) or

SEC-119, "ECM RE-COMMUNICATING FUNCTION : Special Repair Requirement"

(without

Intelligent Key system).

3. Perform

EC-25, "VIN Registration"

4. Perform

EC-25, "Accelerator Pedal Released Position Learning"

5. Perform

EC-25, "Throttle Valve Closed Position Learning"

6. Perform

EC-25, "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 in air cleaner element

• Uneven dirt in air cleaner element

• Improper specification in intake air system
OK or NG

>> GO TO 27.

>> 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

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

>> GO TO 28.

2011 Pathfinder

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-93

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

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.

• 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 in EVAP purge hose, stuck open of EVAP canister purge volume control solenoid

valve

• Malfunctioning seal in rocker cover gasket

• Disconnection, looseness, or cracks in hoses, such as a vacuum hose, connecting to intake air system parts

• Malfunctioning seal in 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 each indication is within the SP value.
OK or NG

INSPECTION END

>> Detect malfunctioning part according to

EC-472, "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

INSPECTION END

>> Detect malfunctioning part according to

EC-472, "Symptom Matrix Chart"

2011 Pathfinder

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