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Infiniti QX56 (Z62). Manual - part 578

EC-290

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0222, P0223 TP SENSOR

Is the inspection result normal?

YES

>> INSPECTION END

>> GO TO 2.

REPLACE ELECTRIC THROTTLE CONTROL ACTUATOR

Replace electric throttle control actuator. Refer to

EM-30, "Removal and Installation"

>> INSPECTION END

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

EC-291

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MIS-
FIRE

DTC Logic

INFOID:0000000006217840

DTC DETECTION LOGIC

When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crank-
shaft position (CKP) sensor signal to vary, ECM can determine that a misfire is occurring.

The misfire detection logic consists of the following two conditions.

One Trip Detection Logic (Three Way Catalyst Damage)
On the 1st trip that a misfire condition occurs that can damage the three way catalyst (TWC) due to over-
heating, the MIL will blink.
When a misfire condition occurs, the ECM monitors the CKP sensor signal every 200 engine revolutions
for a change.
When the misfire condition decreases to a level that will not damage the TWC, the MIL will turn off.
If another misfire condition occurs that can damage the TWC on a second trip, the MIL will blink.
When the misfire condition decreases to a level that will not damage the TWC, the MIL will remain on.
If another misfire condition occurs that can damage the TWC, the MIL will begin to blink again.

Two Trip Detection Logic (Exhaust quality deterioration)
For misfire conditions that will not damage the TWC (but will affect vehicle emissions), the MIL will only
light when the misfire is detected on a second trip. During this condition, the ECM monitors the CKP sen-
sor signal every 1,000 engine revolutions.
A misfire malfunction can be detected in any one cylinder or in multiple cylinders.

DTC CONFIRMATION PROCEDURE

PRECONDITIONING

Turn ignition switch OFF and wait at least 10 seconds.

Turn ignition switch ON.

Turn ignition switch OFF and wait at least 10 seconds.

Sensor

Input signal to ECM

ECM function

Crankshaft position sensor

Engine speed

On board diagnosis of misfire

DTC No.

Trouble diagnosis name

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P0300

MULTI CYL MISFIRE
(Multiple cylinder misfires detected)

Multiple cylinders misfire.

• Improper spark plug
• Insufficient compression
• Incorrect fuel pressure
• The fuel injector circuit is open or shorted
• Fuel injector
• Intake air leakage
• The ignition signal circuit is open or shorted
• Lack of fuel
• Signal plate
• A/F sensor 1
• Incorrect PCV hose connection

P0301

CYL 1 MISFIRE
(No.1 cylinder misfire detected)

No. 1 cylinder misfires.

P0302

CYL 2 MISFIRE
(No. 2 cylinder misfire detected)

No. 2 cylinder misfires.

P0303

CYL 3 MISFIRE
(No. 3 cylinder misfire detected)

No. 3 cylinder misfires.

P0304

CYL 4 MISFIRE
(No. 4 cylinder misfire detected)

No. 4 cylinder misfires.

P0305

CYL 5 MISFIRE
(No. 5 cylinder misfire detected)

No. 5 cylinder misfires.

P0306

CYL 6 MISFIRE
(No. 6 cylinder misfire detected)

No. 6 cylinder misfires.

P0307

CYL 7 MISFIRE
(No. 7 cylinder misfire detected)

No. 7 cylinder misfires.

P0308

CYL 8 MISFIRE
(No. 8 cylinder misfire detected)

No. 8 cylinder misfires.

EC-292

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

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

>> GO TO 2.

PERFORM DTC CONFIRMATION PROCEDURE-I

Start engine and warm it up to normal operating temperature.

Turn ignition switch OFF and wait at least 10 seconds.

Turn ignition switch ON.

Turn ignition switch OFF and wait at least 10 seconds.

Restart engine and let it idle for about 15 minutes.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to

EC-292, "Diagnosis Procedure"

>> GO TO 3.

PERFORM DTC CONFIRMATION PROCEDURE-II

Turn ignition switch OFF and wait at least 10 seconds.

Turn ignition switch ON.

Turn ignition switch OFF and wait at least 10 seconds.

Start engine and drive the vehicle under similar conditions to (1st trip) Freeze Frame Data for a certain
time. Refer to the table below.
Hold the accelerator pedal as steady as possible.
Similar conditions to (1st trip) Freeze Frame Data mean that the following conditions should be satisfied at
the same time.

CAUTION:

Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws when
driving.

Driving time varies according to the engine speed in the freeze frame data.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to

EC-292, "Diagnosis Procedure"

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006217841

CHECK FOR INTAKE AIR LEAKAGE AND PCV HOSE

Start engine and run it at idle speed.

Listen for the sound of the intake air leakage.

Check PCV hose connection.

Is intake air leakage detected?

YES

>> Discover air leakage location and repair.

>> GO TO 2.

CHECK FOR EXHAUST SYSTEM CLOGGING

Engine speed

Engine speed in the freeze frame data

400 rpm

Vehicle speed

Vehicle speed in the freeze frame data

10 km/h (6 MPH)

Base fuel schedule

Base fuel schedule in the freeze frame data

0.1)

Engine coolant temperature (T)
condition

When the freeze frame data shows lower than 70

C (158

F),

T should be lower than 70

C (158

F).

When the freeze frame data shows higher than or equal to 70

C (158

F),

T should be higher than or equal to 70

C (158

F).

Engine speed

Time

Around 1,000 rpm

Approximately 10 minutes

Around 2,000 rpm

Approximately 5 minutes

More than 3,000 rpm

Approximately 3.5 minutes

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

EC-293

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.

Is the inspection result normal?

YES-1 >> With CONSULT-III: GO TO 3.
YES-2 >> Without CONSULT-III: GO TO 4.
NO

>> Repair or replace malfunctioning part.

PERFORM POWER BALANCE TEST

WITH CONSULT-III

Start engine.

Perform “POWER BALANCE” in “ACTIVE TEST” mode with CONSULT-III.

Check that each circuit produces a momentary engine speed drop.

Is the inspection result normal?

YES

>> GO TO 9.

>> GO TO 4.

CHECK FUNCTION OF FUEL INJECTOR-I

Start engine and let it idle.

Listen to each fuel injector operation.

Is the inspection result normal?

YES

>> GO TO 5.

>> Perform trouble diagnosis for FUEL INJECTOR, refer to

EC-498, "Diagnosis Procedure"

CHECK FUNCTION OF IGNITION COIL-I

CAUTION:

Perform the following procedure in a place with no combustible objects and good ventilation.
1.

Turn ignition switch OFF.

Remove fuel pump fuse No. in IPDM E/R to release fuel pressure.
NOTE:
Do not use CONSULT-III to release fuel pressure, or fuel pressure applies again during the following pro-
cedure.

Start engine.

After engine stalls, crank it 2 or 3 times to release all fuel pressure.

Turn ignition switch OFF.

Remove all ignition coil harness connectors to avoid the electrical discharge from the ignition coils.

Remove ignition coil and spark plug of the cylinder to be checked.

Crank engine for 5 seconds or more to remove combustion gas in the cylinder.

Connect spark plug and harness connector to ignition coil.

10. Fix ignition coil using a rope etc. with gap of 13 - 17 mm (0.52 -

0.66 in) between the edge of the spark plug and grounded metal
portion as shown in the figure.

11. Crank engine for approximately 3 seconds, and check whether

spark is generated between the spark plug and the grounded
metal portion.

CAUTION:

• Never place the spark plug and the ignition coil within 50

cm (19.7 in) each other. Be careful not to get an electrical
shock while checking, because the electrical discharge
voltage becomes 20 kV or more.

• It might damage the ignition coil if the gap of more than 17 mm (0.66 in) is made.
NOTE:

Clicking sound should be heard.

PBIB3332E

Spark should be generated.

JMBIA0066GB

Content .. 576 577 578 579 ..