Infiniti QX56 (Z62). Manual - part 633

EC-510

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

IGNITION SIGNAL

3.

Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
• For the fuse number, refer to 

EC-114, "Wiring Diagram"

.

• For the fuse arrangement, refer to 

PG-143, "Fuse, Connector and Terminal Arrangement"

.

• Do not use CONSULT-III to release fuel pressure, or fuel pressure applies again during the following

procedure.

4.

Start engine.

5.

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

6.

Turn ignition switch OFF.

7.

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

8.

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

9.

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

10. Connect spark plug and harness connector to ignition coil.
11. 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.

12. 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:
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

>> INSPECTION END

NO

>> Replace malfunctioning ignition coil with power transistor.

Component Inspection (Condenser)

INFOID:0000000006218014

1.

CHECK CONDENSER

1.

Turn ignition switch OFF.

2.

Disconnect condenser harness connector.

3.

Check resistance between condenser terminals as per the following.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace condenser.

Spark should be generated.

JMBIA0066GB

Terminals

Resistance

1 and 2

Above 1 M

Ω

 [at 25

°

C (77

°

F)]

INFORMATION DISPLAY (ASCD)

EC-511

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

C

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EC

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INFORMATION DISPLAY (ASCD)

Component Function Check

INFOID:0000000006218015

1.

CHECK INFORMATION DISPLAY

1.

Start engine.

2.

Press MAIN switch on ASCD steering switch.

3.

Drive the vehicle at more than 40 km/h (25 MPH).

CAUTION:

Always drive vehicle at a safe speed.

4.

Press SET/COAST switch.

5.

Check that the reading of the speedometer shows the same value as the set speed indicated in the infor-
mation display while driving the vehicle on a flat road.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-511, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000006218016

1.

CHECK DTC

Check that DTC UXXXX or P0500 is not displayed.

Is the inspection result normal?

YES

>> GO TO 2.

NO-1

>> Perform trouble diagnosis for DTC UXXXX.

NO-2

>> Perform trouble diagnosis for DTC P0500. Refer to 

EC-356, "DTC Logic"

.

2.

CHECK DTC WITH “COMBINATION METER”

Refer to 

MWI-30, "CONSULT-III Function"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Perform trouble diagnosis for DTC indicated.

3.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-40, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> Replace combination meter.

NO

>> Repair or replace.

EC-512

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

LOW PRESSURE FUEL PUMP

LOW PRESSURE FUEL PUMP

Component Function Check

INFOID:0000000006218017

1.

CHECK FUEL PUMP FUNCTION

1.

Turn ignition switch ON.

2.

Pinch fuel feed hose with two fingers.
NOTE:
Fuel pressure pulsation should be felt on the fuel feed hose for 1 second after ignition switch is turned ON.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>>

EC-512, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000006218018

1.

CHECK FPCM POWER SUPPLY CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect FPCM harness connector.

3.

Turn ignition switch ON.

4.

Check the voltage between FPCM harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Perform the trouble diagnosis for power supply circuit. Refer to 

EC-168, "Diagnosis Procedure"

.

2.

CHECK FPCM GROUND CIRCUIT

1.

Turn ignition switch OFF.

2.

Check the continuity between FPCM harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

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

3.

CHECK FPCM INPUT AND OUTPUT CIRCUIT

1.

Disconnect ECM harness connector.

2.

Check the continuity between FPCM harness connector and ECM harness connector.

3.

Also check harness for short to ground and to power.

Is the inspection result normal?

+

−

Voltage

FPCM

Connector

Terminal

B41

10

Ground

Battery voltage

+

−

Continuity

FPCM

Connector

Terminal

B41

5

Ground

Existed

+

−

Continuity

FPCM

ECM

Connector

Terminal

Connector

Terminal

B41

8

E80

125

Existed

9

142

LOW PRESSURE FUEL PUMP

EC-513

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

C

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F

G

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EC

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O

YES

>> GO TO 4.

NO

>> Repair or replace error-detected parts.

4.

CHECK FUEL PUMP CONTROL CIRCUIT

1.

Disconnect fuel level sensor unit and fuel pump harness connector.

2.

Check the continuity between FPCM harness connector and fuel level sensor unit and fuel pump harness
connector.

3.

Also check harness for short to ground and to power.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair or replace error-detected parts.

5.

CHECK LOW PRESSURE FUEL PUMP

Refer to 

EC-513, "Component Inspection (Low Pressure Fuel Pump)"

.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Replace fuel level sensor unit and fuel pump. Refer to 

FL-5, "Removal and Installation"

.

6.

CHECK FPCM

Refer to 

EC-514, "Component Inspection (FPCM)"

.

Is the inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-40, "Intermittent Incident"

.

NO

>> Replace FPCM. Refer to 

EC-537, "Removal and Installation"

.

Component Inspection (Low Pressure Fuel Pump)

INFOID:0000000006218019

1.

CHECK FUEL PRESSURE REGULATOR

1.

Turn ignition switch OFF.

2.

Check low fuel pressure. Refer to 

EC-153, "Work Procedure"

.

Is inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

CHECK LOW PRESSURE FUEL PUMP

1.

Turn ignition switch OFF.

2.

Disconnect fuel level sensor unit and fuel pump.

3.

Check resistance between fuel level sensor unit and fuel pump terminals as follows.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace fuel level sensor unit and fuel pump.  Refer to 

FL-5, "Removal and Installation"

.

+

−

Continuity

FPCM

Fuel level sensor unit and fuel pump

Connector

Terminal

Connector

Terminal

B41

6

C5

3

Existed

7

1

+

−

Condition

Resistance

Fuel level sensor unit and fuel 

pump

Terminals

1

3

Temperature: 25

°

C (77

°

F)

0.2 - 5.0 

Ω