Nissan Quest E52. Manual - part 487

EC-158

< DTC/CIRCUIT DIAGNOSIS >

[VQ35DE]

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

NOTE:
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.

Is the measurement value within the SP value?

YES

>> GO TO 17.

NO-1

>> Less than the SP value: GO TO 2.

NO-2

>> More than the SP value: GO TO 3.

2.

CHECK “B/FUEL SCHDL”

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

Is the measurement value within the SP value?

YES

>> GO TO 4.

NO

>> More than the SP value: GO TO 19.

3.

CHECK “B/FUEL SCHDL”

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

Is the measurement value within the SP value?

YES

>> GO TO 6.

NO-1

>> More than the SP value: GO TO 6.

NO-2

>> 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 check that each
indication is within the SP value.

Is the measurement value within the SP value?

YES

>> GO TO 5.

NO

>> 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-
ditions.

>> INSPECTION END

6.

CHECK FUEL PRESSURE

Check fuel pressure. (Refer to 

EC-141, "Work Procedure"

.)

Is the inspection result normal?

YES

>> GO TO 9.

NO-1

>> Fuel pressure is too high: Replace “fuel filter and fuel pump assembly”, refer to 

FL-5, "Exploded

View"

, and then GO TO 8.

NO-2

>> Fuel pressure is too low: GO TO 7.

7.

DETECT MALFUNCTIONING PART

Check fuel hoses and fuel tubes for clogging.

Is the inspection result normal?

YES

>> Replace “fuel filter and fuel pump assembly”, refer to 

FL-5, "Exploded View"

, and then GO TO 8.

NO

>> Repair or replace malfunctioning part and then GO TO 8.

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-159

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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 check that each
indication is within the SP value.

Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> GO TO 9.

9.

PERFORM POWER BALANCE TEST

1.

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

2.

Check that the each cylinder produces a momentary engine speed drop.

Is the inspection result normal?

YES

>> GO TO 12.

NO

>> GO TO 10.

10.

DETECT MALFUNCTIONING PART

Check the following below.
• Ignition coil and its circuit (Refer to 

EC-431, "Component Function Check"

.)

• Fuel injector and its circuit (Refer to 

EC-426, "Component Function Check"

.)

• Intake air leakage
• Low compression pressure (Refer to 

EM-23, "Inspection"

.)

Is the inspection result normal?

YES

>> Replace fuel injector, refer to 

EM-47, "Exploded View"

, and then GO TO 11.

NO

>> Repair or replace malfunctioning part and then 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 check that each
indication is within the SP value.

Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> 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-206, "DTC Logic"

.

• For DTC P0131, P0151, refer to 

EC-210, "DTC Logic"

.

• For DTC P0132, P0152, refer to 

EC-213, "DTC Logic"

.

• For DTC P014C, P014D, P014E, P014F, refer to 

EC-235, "DTC Logic"

.

• For DTC P2096, P2097, P2098, P2099, refer to 

EC-391, "DTC Logic"

.

Are any DTCs detected?

YES

>> GO TO 15.

NO

>> 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 check that each
indication is within the SP value.

Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> GO TO 15.

EC-160

< DTC/CIRCUIT DIAGNOSIS >

[VQ35DE]

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

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 check that each
indication is within the SP value.

Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> Detect malfunctioning part according to 

EC-450, "Symptom Table"

.

17.

CHECK “B/FUEL SCHDL”

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

Is the measurement value within the SP value?

YES

>> INSPECTION END

NO-1

>> More than the SP value: GO TO 18.

NO-2

>> 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
Is the inspection result normal?

YES

>> GO TO 21.

NO

>> 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
check that each indication is within the SP value.
Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> “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.

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-161

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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 check that each
indication is within the SP value.

Is the measurement value within the SP value?

YES

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

EC-184, "Diagno-

sis Procedure"

. Then GO TO 29.

NO

>> GO TO 23.

23.

CHECK “MAS A/F SE-B1”

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

Is the measurement value within the SP value?

YES

>> GO TO 24.

NO

>> More than the SP value: Replace mass air flow sensor, refer to 

EM-26, "Exploded View"

, and then

GO TO 29.

24.

REPLACE ECM

1.

Replace ECM.

2.

Refer to 

EC-133, "Work Procedure"

.

>> 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

Is the inspection result normal?

YES

>> GO TO 27.

NO

>> 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 check that the indication is within the SP
value.

Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> 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 check that the indication is within the SP
value.

Is the measurement value within the SP value?

YES

>> GO TO 28.

NO

>> Less than the SP value: Replace mass air flow sensor, refer to 

EM-26, "Exploded View"

,and then

GO TO 30.

28.

CHECK INTAKE SYSTEM

Check for the cause of air leakage 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