Infiniti QX56 (Z62). Manual - part 626

EC-482

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P2138 APP SENSOR

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

REPLACE ACCELERATOR PEDAL ASSEMBLY

Replace accelerator pedal assembly. Refer to 

ACC-3, "MODELS WITHOUT DISTANCE CONTROL ASSIST

SYSTEM : Removal and Installation"

 (Without distance control assist system) or 

ACC-4, "MODELS WITH

DISTANCE CONTROL ASSIST SYSTEM : Removal and Installation"

 (With distance control assist system).

>> INSPECTION END

P2539, P2541, P2542 LOW FUEL PRESSURE SENSOR

EC-483

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

P2539, P2541, P2542 LOW FUEL PRESSURE SENSOR

DTC Logic

INFOID:0000000006288355

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 11 V or more at idle.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Start engine and let it idle for at least 60 seconds.

2.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Proceed to 

EC-483, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006288356

1.

CHECK LOW FUEL PRESSURE SENSOR POWER SUPPLY-I

1.

Turn ignition switch OFF.

2.

Disconnect low fuel pressure sensor connector.

3.

Turn ignition switch ON.

4.

Check the voltage between low fuel pressure sensor harness connector terminals.

Inspection result normal?

YES

>> GO TO 6.

NO

>> GO TO 2.

2.

CHECK LOW FUEL PRESSURE SENSOR POWER SUPPLY-II

Check the voltage between low fuel pressure sensor harness connector and the ground.

DTC No.

Trouble diagnosis name

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P2539

LOW FUEL PRES SEN
(Low fuel pressure sensor 
circuit low input and high in-
put)

Signal voltage from the low fuel pressure 
sensor remains at more than 4.84 V / less 
than 0.3 V for 5 seconds or more.

• Harness or connectors

(Low fuel pressure sensor circuit is open 
or shorted.)
(Power steering pressure sensor circuit is 
open or shorted.)
(Cooling fan speed sensor circuit is open 
or shorted.)
(FRP sensor circuit is open or shorted.)

• Low fuel pressure sensor
• Power steering pressure sensor
• Cooling fan speed sensor
• FRP sensor

P2541

LOW FUEL PRES SEN
(Low fuel pressure sensor 
circuit low input)

Signal voltage from the low fuel pressure 
sensor remains at less than 0.49 V for 5 sec-
onds or more.

P2542

LOW FUEL PRES SEN
(Low fuel pressure sensor 
circuit high input)

Signal voltage from the low fuel pressure 
sensor remains at more than 4.1 V for 5 sec-
onds or more.

Low fuel pressure sensor

Voltage

(Approx.)

Connector

+

−

terminal

F25

3

1

5 V

EC-484

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P2539, P2541, P2542 LOW FUEL PRESSURE SENSOR

Is inspection result normal?

YES

>> GO TO 4.

NO

>> GO TO 3.

3.

CHECK SENSOR POWER SUPPLY CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check harness connector for short to power and short to ground, between the following terminals.

Is inspection result normal?

YES

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

EC-168, "Diagnosis Procedure"

.

NO

>> Repair or replace error-detected parts.

4.

CHECK LOW FUEL PRESSURE SENSOR GROUND CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between low fuel pressure sensor harness connector and ECM harness connector.

Is inspection result normal?

YES

>> GO TO 5.

NO

>> Repair or replace error-detected parts.

5.

CHECK ECM GROUND CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between ECM harness connector and the ground.

Is inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-40, "Intermittent Incident"

.

+

−

Voltage

(Approx.)

Low fuel pressure sensor

Connector

Terminal

F25

3

Ground

5 V

ECM

Sensor

Connector

Terminal

Name

Connector

Terminal

F111

27

Power steering pressure sensor

F35

1

Low fuel pressure sensor

F25

3

Cooling fan speed sensor

F39

2

28

FRP sensor

F26

1

+

−

Continuity

Low fuel pressure sensor

ECM

Connector

Terminal

Connector

Terminal

F25

1

F111

45

Existed

ECM

Ground

Continuity

Connector

Terminal

F111

5

Ground

Existed

E80

114

115

174

175

P2539, P2541, P2542 LOW FUEL PRESSURE SENSOR

EC-485

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

C

D

E

F

G

H

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J

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M

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EC

N

P

O

NO

>> Repair or replace error-detected parts.

6.

CHECK LOW FUEL PRESSURE SENSOR SIGNAL CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between low fuel pressure sensor harness connector and ECM harness connector.

4.

Also check harness for short to ground and to power.

Is inspection result normal?

YES

>> GO TO 7.

NO

>> Repair or replace error-detected parts.

7.

CHECK LOW FUEL PRESSURE SENSOR 

Refer to 

EC-485, "Component Inspection"

.

Is inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-40, "Intermittent Incident"

.

NO

>> Replace low fuel pressure sensor.

Component Inspection

INFOID:0000000006289706

1.

CHECK LOW FUEL PRESSURE SENSOR

WITH CONSULT-III

1.

Turn ignition switch OFF.

2.

Reconnect harness connector disconnected.

3.

Start the engine.

4.

Select “DATA MONITOR” mode with CONSULT-III.

5.

Check that the “L/FUEL PRES SEN V” value. 

WITHOUT CONSULT-III

1.

Turn ignition switch OFF.

2.

Reconnect harness connector disconnected.

3.

Start the engine.

4.

Check low fuel pressure sensor signal voltage.

+

−

Continuity

Low fuel pressure sensor

ECM

Connector

Terminal

Connector

Terminal

F25

2

F111

23

Existed

Data monitor item

Condition

Value

(Approx.)

L/FUEL PRES SEN V

Engine speed: idle

3,000 –3,300 mV

Engine speed: 3,000 rpm (no load)