Infiniti QX56 (Z62). Manual - part 579

EC-294

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MISFIRE

When the gap is less than 13 mm (0.52 in), a spark might be generated even if the coil is malfunc-
tioning.

Is the inspection result normal?

YES

>> GO TO 9.

NO

>> GO TO 6.

6.

CHECK FUNCTION OF IGNITION COIL-II

1.

Turn ignition switch OFF.

2.

Disconnect spark plug and connect a non-malfunctioning spark plug.

3.

Crank engine for approximately 3 seconds, and recheck whether spark is generated between the spark
plug and the grounded metal portion.

Is the inspection result normal?

YES

>> GO TO 7.

NO

>> Check ignition coil, power transistor and their circuits. Refer to 

EC-506, "Diagnosis Procedure"

.

7.

CHECK SPARK PLUG

Check the initial spark plug for fouling, etc.

Is the inspection result normal?

YES

>> Replace spark plug(s) with standard type one(s). For

spark plug type, refer to 

EM-132, "Spark Plug"

.

NO

>> Repair or clean spark plug. Then GO TO 8.

8.

CHECK FUNCTION OF IGNITION COIL-III

1.

Reconnect the initial spark plugs.

2.

Crank engine for approximately 3 seconds, and recheck whether spark is generated between the spark
plug and the grounded portion.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace spark plug(s) with standard type one(s). For spark plug type, refer to 

EM-132, "Spark

Plug"

.

9.

CHECK COMPRESSION PRESSURE

Check compression pressure. Refer to 

EM-16, "Inspection"

.

Is the inspection result normal?

YES

>> GO TO 10.

NO

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

10.

CHECK FUEL PRESSURE

1.

Install all removed parts.

2.

Check fuel pressure. Refer to 

EC-153, "Work Procedure"

.

Is the inspection result normal?

YES

>> GO TO 12.

NO

>> GO TO 11.

11.

DETECT MALFUNCTIONING PART

Check fuel hoses and fuel tubes for clogging.

Is the inspection result normal?

Spark should be generated.

SEF156I

Spark should be generated.

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MISFIRE

EC-295

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

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YES

>> Replace “fuel filter and fuel pump assembly”.

NO

>> Repair or replace malfunctioning part.

12.

CHECK IDLE SPEED AND IGNITION TIMING

Check idle speed and ignition timing.
For procedure, refer to 

EC-530, "Inspection"

 and 

EC-531, "Inspection"

.

For specification, refer to 

EC-538, "Idle Speed"

 and 

EC-538, "Ignition Timing"

.

Is the inspection result normal?

YES

>> GO TO 13.

NO

>> Follow the 

EC-139, "Work Procedure"

.

13.

CHECK AIR FUEL RATIO SENSOR 1 POWER SUPPLY CIRCUIT

1.

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

2.

Turn ignition switch ON.

3.

Check the voltage between A/F sensor 1 harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 14.

NO

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

14.

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between A/F sensor 1 harness connector and ECM harness connector.

4.

Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector
and ground.

5.

Also check harness for short to power.

Is the inspection result normal?

YES

>> GO TO 15.

NO

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

15.

CHECK A/F SENSOR 1 GROUND CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between A/F sensor 1 harness connector and ECM harness connector.

DTC

A/F sensor 1

Ground

Voltage

Bank

Connector

Terminal

P0130

1

F67

4

Ground

3.0 V

P0150

2

F68

4

DTC

A/F sensor 1

ECM

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0130

1

F67

3

F110

88

Existed

P0150

2

F68

3

78

DTC

A/F sensor 1

ECM

Ground

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0130

1

F67

3

F110

88

Ground

Not existed

P0150

2

F68

3

78

EC-296

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MISFIRE

4.

Also check harness for short to power.

Is the inspection result normal?

YES

>> GO TO 16.

NO

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

16.

CHECK A/F SENSOR 1 HEATER

Refer to 

EC-182, "Component Inspection (A/F Sensor 1 Heater)"

.

Is the inspection result normal?

YES

>> GO TO 17.

NO

>> Replace malfunctioning A/F sensor 1. Refer to 

EX-5, "Exploded View"

.

17.

CHECK MASS AIR FLOW SENSOR

 WITH CONSULT-III

Check mass air flow sensor signal in “DATA MONITOR” mode with CONSULT-III.
For specification, refer to 

EC-538, "Mass Air Flow Sensor"

.

 WITH GST

Check mass air flow sensor signal in Service $01 with GST.
For specification, refer to 

EC-538, "Mass Air Flow Sensor"

.

Is the measurement value within the specification?

YES

>> GO TO 18.

NO

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

ground. Refer to 

EC-201, "Diagnosis Procedure"

.

18.

CHECK SYMPTOM MATRIX CHART

Check items on the rough idle symptom in 

EC-524, "Symptom Table"

.

Is the inspection result normal?

YES

>> GO TO 19.

NO

>> Repair or replace malfunctioning part.

19.

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-63, "CONSULT-III

Function"

 or 

EC-60, "On Board Diagnosis Function"

.

>> GO TO 20.

20.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-40, "Intermittent Incident"

.

>> INSPECTION END

DTC

A/F sensor 1

ECM

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0130

1

F67

6

F110

94

Existed

P0150

2

F68

6

74

P0327, P0328, P0332, P0333 KS

EC-297

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

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P0327, P0328, P0332, P0333 KS

DTC Logic

INFOID:0000000006217842

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

1.

Turn ignition switch OFF and wait at least 10 seconds.

2.

Turn ignition switch ON.

3.

Turn ignition switch OFF and wait at least 10 seconds.

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is 10 V or more at idle.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Start engine and run it for at least 5 seconds at idle speed.

2.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-297, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006217843

1.

CHECK KNOCK SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1.

Disconnect knock sensor harness connector and ECM harness connector.

2.

Check the continuity between knock sensor harness connector and ECM harness connector.

3.

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

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 2.

2.

DETECT MALFUNCTIONING PART

Check the following.

DTC No.

Trouble diagnosis name

(Trouble diagnosis content)

DTC detected condition

Possible cause

P0327

KNOCK SEN/CIRC-B1
[Knock sensor (bank 1) circuit 
low input]

An excessively low voltage from the sensor 
is sent to ECM.

• Harness or connectors

(The knock sensor circuit is open or 
shorted.)

• Knock sensor

P0328

KNOCK SEN/CIRC-B1
[Knock sensor (bank 1) circuit 
high input]

An excessively high voltage from the sensor 
is sent to ECM.

P0332

KNOCK SEN/CIRC-B2
[Knock sensor (bank 2) circuit 
low input]

An excessively low voltage from the sensor 
is sent to ECM.

P0333

KNOCK SEN/CIRC-B2
[Knock sensor (bank 2) circuit 
high input]

An excessively high voltage from the sensor 
is sent to ECM.

DTC

Knock sensor

ECM

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0327, P0328

1

F203

2

F111

35

Existed

P0332, P0333

2

F204

2