Nissan Qashqai (2007-2010). Manual - part 302

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-727

< COMPONENT DIAGNOSIS >

[MR20DE (WITH EURO-OBD)]

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OVERALL SEQUENCE

PBIB2384E

EC-728

< COMPONENT DIAGNOSIS >

[MR20DE (WITH EURO-OBD)]

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

DETAILED PROCEDURE

1.

CHECK “A/F ALPHA-B1”

With CONSULT-III

1.

Start engine.

2.

Confirm that the testing conditions are met. Refer to 

EC-728, "Component Function Check"

.

3.

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

PBIB3213E

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

EC-729

< COMPONENT DIAGNOSIS >

[MR20DE (WITH EURO-OBD)]

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NOTE:
Check “A/F ALPHA-B1” 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 make sure 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 make sure 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”

1.

Stop the engine.

2.

Disconnect PCV hose, and then plug it.

3.

Start engine.

4.

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

>> INSPECTION END

6.

CHECK FUEL PRESSURE

Check fuel pressure. (Refer to 

EC-978, "Inspection"

.)

Is the inspection result normal?

YES

>> GO TO 9.

NO-1

>> Fuel pressure is too high: Replace “fuel filter and fuel pump assembly” 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” and then GO TO 8.

NO

>> Repair or replace and then GO TO 8.

8.

CHECK “A/F ALPHA-B1”

EC-730

< COMPONENT DIAGNOSIS >

[MR20DE (WITH EURO-OBD)]

TROUBLE DIAGNOSIS - SPECIFICATION VALUE

1.

Start engine.

2.

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

Make sure 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.
1.

Ignition coil and its circuit (Refer to 

EC-929, "Component Function Check"

.)

2.

Fuel injector and its circuit (Refer to 

EC-923, "Component Function Check"

.)

3.

Intake air leakage

4.

Low compression pressure (Refer to 

EM-142, "Inspection"

.)

Is the inspection result normal?

YES

>> Replace fuel injector and then GO TO 11.

NO

>> Repair or replace malfunctioning part and then GO TO 11.

11.

CHECK “A/F ALPHA-B1”

1.

Start engine.

2.

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

Is the measurement value within the SP value?

YES

>> INSPECTION END

NO

>> GO TO 12.

12.

CHECK HEATED OXYGEN SENSOR 1 FUNCTION

1.

Run engine at about 2,000 rpm for about 2minutes under no load.

2.

Select “HO2S MNTR (B1)”, in “DATA MONITOR” mode.

3.

Running engine at 2,000 rpm under no load (The engine is
warmed up to normal operating temperature.), check that the
monitor fluctuates between LEAN and RICH more than 5 times
during 10 seconds.

Is the inspection result more than 5 times during 10 seconds?

YES

>> GO TO 15.

NO

>> GO TO 13.

13.

CHECK HEATED OXYGEN SENSOR 1 CIRCUIT

Check heated oxygen sensor 1 and its circuit, refer to.

>> GO TO 14.

14.

CHECK “A/F ALPHA-B1”

1.

Start engine.

2.

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

Is the measurement value within the SP value?

YES

>> INSPECTION END

1 time

: RICH 

→

 LEAN 

→

 RICH

2 times

: RICH 

→

 LEAN 

→

 RICH 

→

 LEAN 

→

 RICH

SEF820Y