Infiniti QX56 (Z62). Manual - part 575

EC-278

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0190, P0192, P0193 FRP SENSOR

6.

CHECK FRP SENSOR SIGNAL CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between FRP 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 FRP SENSOR

Refer to 

EC-278, "Component Inspection (Fuel Rail Pressure Sensor)"

.

Is inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-40, "Intermittent Incident"

.

NO

>> Repair or replace error-detected parts.

Component Inspection (Fuel Rail Pressure Sensor)

INFOID:0000000006288297

1.

CHECK FRP 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 “FUEL PRES SEN V” indication. 

WITHOUT CONSULT-III

1.

Turn ignition switch OFF.

2.

Reconnect harness connector disconnected.

3.

Start the engine.

4.

Check FRP sensor signal voltage.

Is the inspection result normal? 

YES

>> INSPECTION END.

NO

>> Replace FRP sensor. Refer to 

EM-48, "Exploded View"

.

+

−

Continuity

FRP sensor

ECM

Connector

Terminal

Connector

Terminal

F26

2

F111

31

Existed

Monitor Item

Condition

Values/Status

FUEL PRES SEN V

Engine speed: Idle

980 – 1,200 mV

Engine speed: Revving engine from idle to 4,000 rpm 
quickly

1,100 – 2,900 mV

+

−

Condition

Value

(Approx.)

ECM

Connector

Terminal

Connector

Terminal

F111

31

F111

40

[Engine is running]
• Warm-up condition
• Idle speed

0.98 – 1.2 V

[Engine is running]
• Warm-up condition
• Revving engine from idle to 4,000 rpm quickly

1.1 – 2.9 V

P0191 FRP SENSOR

EC-279

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

C

D

E

F

G

H

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EC

N

P

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P0191 FRP SENSOR

DTC Logic

INFOID:0000000006288298

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 the engine and warm it up to the normal operating temperature.
NOTE:
Warm up the engine until “COOLAN TEMP/S” on “DATA MONITOR” of CONSULT-III reaches at least
70

°

C (158

°

F).

2.

Turn the ignition switch OFF and cool the engine until the engine coolant temperature reaches 35

°

C

(95

°

F) or less.

CAUTION:

• The difference between air temperature and engine coolant temperature must be 5

°

C or less.

• Do not turn ignition switch ON.

3.

Turn ignition switch ON and wait at least 60 seconds.

4.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Proceed to 

EC-279, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006288299

1.

CHECK FRP SENSOR POWER SUPPLY-I

1.

Turn ignition switch OFF.

2.

Disconnect FRP sensor connector.

3.

Turn ignition switch ON.

4.

Check the voltage between FRP sensor harness connector terminals.

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0191

Fuel rail pressure sensor

Fuel rail pressure remains at more than 

1.5 MPa (15 bar, 15.3 kg/cm

2

, 217.5 psi) 

for 0.2 seconds or more during ignition 
ON.

• Harness or connectors

(Fuel rail pressure sensor circuit is open or 
shorted.)
(Power steering pressure sensor circuit is 
open or shorted.)
(Low fuel pressure sensor circuit is open or 
shorted.)
(The electrically-controlled cooling fan cou-
pling circuit is open or shorted)

• Fuel rail pressure sensor
• Power steering pressure sensor
• Low fuel pressure sensor
• Electrically-controlled cooling fan coupling

EC-280

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0191 FRP SENSOR

Inspection result normal?

YES

>> GO TO 6.

NO

>> GO TO 2.

2.

CHECK FRP SENSOR POWER SUPPLY-II

Check the voltage between FRP sensor harness connector and the ground.

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 FRP SENSOR GROUND CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between FRP 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

Check the continuity between ECM harness connector and the ground.

FRP sensor

Voltage

(Approx.)

Connector

+

−

terminal

F26

1

3

5 V

+

−

Voltage

(Approx.)

FRP sensor

Connector

Terminal

F26

1

Ground

5 V

ECM

Sensor

Connector

Terminal

Name

Connector

Terminal

F111

27

Low fuel pressure sensor

F25

3

Power steering pressure sensor

F35

1

Cooling fan speed sensor

F39

2

28

FRP sensor

F26

1

+

−

Continuity

FRP sensor

ECM

Connector

Terminal

Connector

Terminal

F26

3

F111

40

Existed

P0191 FRP SENSOR

EC-281

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

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G

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EC

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P

O

Is inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-40, "Intermittent Incident"

.

NO

>> Repair or replace error-detected parts.

6.

CHECK FRP SENSOR SIGNAL CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between FRP 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 FRP SENSOR

Refer to 

EC-278, "Component Inspection (Fuel Rail Pressure Sensor)"

.

Is inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-40, "Intermittent Incident"

.

NO

>> Repair or replace error-detected parts.

Component Inspection (Fuel Rail Pressure Sensor)

INFOID:0000000006288360

1.

CHECK FRP 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 “FUEL PRES SEN V” indication. 

WITHOUT CONSULT-III

1.

Turn ignition switch OFF.

2.

Reconnect harness connector disconnected.

3.

Start the engine.

4.

Check FRP sensor signal voltage.

ECM

Ground

Continuity

Connector

Terminal

F111

5

Ground

Existed

E80

114

115

174

175

+

−

Continuity

FRP sensor

ECM

Connector

Terminal

Connector

Terminal

F26

2

F111

31

Existed

Monitor Item

Condition

Values/Status

FUEL PRES SEN V

Engine speed: Idle

980 – 1,200 mV

Engine speed: Revving engine from idle to 4,000 rpm 
quickly

1,100 – 2,900 mV