2011 INFINITI QX56 fuel pressure

P0461 FUEL LEVEL SENSOREC-353
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P0461 FUEL LEVEL SENSOR
DTC LogicINFOID:0000000006288330
DTC DETECTION LOGIC
NOTE:

If DTC P0461 is displayed with DTC UXXXX, first perform the tr ouble diagnosis for DTC UXXXX.
 If DTC P0461 is displayed with DT C P0607, first perform the trouble diagnosis for DTC P0607. Refer
to EC-378, "
DTC Logic".
Driving long distances naturally affect fuel gauge level.
This diagnosis detects the fuel gauge malfunction of the gauge not moving even after a long distance has
been driven.
DTC CONFIRMATION PROCEDURE
1.PERFORM COMPONENT FUNCTION CHECK
Perform Component Function Check. Refer to EC-353, "
Component Function Check".
Use component function check to check the overall function of the fuel level sensor. During this check, a 1st
trip DTC might not be confirmed.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Proceed to EC-354, "
Diagnosis Procedure".
Component Function CheckINFOID:0000000006288331
1.PRECONDITIONING
WARNING:
When performing the following procedure, alw ays observe the handling of the fuel. Refer to FL-2,
"General Precautions".
TESTING CONDITION:
Before starting component function check, preparation of draining fuel and refilling fuel is required.
>> GO TO 2.
2.PERFORM COMPONENT FUNCTION CHECK
NOTE:
Start from step 8, if it is possible to confirm that the fuel cannot be drained by 30 (7-7/8 US gal, 6-5/8
Imp gal) in advance.
1. Prepare a fuel container and a spare hose.
2. Release fuel pressure from fuel line. Refer to EC-153, "
Work Procedure".
3. Remove the fuel feed hose on the fuel level sensor unit. Refer to FL-5, "
Removal and Installation".
4. Connect a spare fuel hose where the fuel feed hose was removed.
5. Turn ignition switch ON.
6. Drain fuel by 30 (7-7/8 US gal, 6-5/8 Imp gal) from the fuel tank using proper equipment.
7. Confirm that the fuel gauge indication varies.
8. Fill fuel into the fuel tank for 30 (7-7/8 US gal, 6-5/8 Imp gal).
9. Confirm that the fuel gauge indication varies.
Is the inspection result normal?
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0461 FUEL LEVEL SENSOR
(Fuel level sensor circuit
range/performance) The output signal of the fuel level sensor
does not change within the specified
range even though the vehicle has been
driven a long distance.  Harness or connectors
(The CAN communication line is open or short-
ed)
 Harness or connectors (The sensor circuit is open or shorted)
 Combination meter
 Fuel level sensor
Revision: 2010 May2011 QX56

P0527 COOLING FAN SPEED SENSOREC-367
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P0527 COOLING FAN SPEED SENSOR
DTC LogicINFOID:0000000006217867
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 warm it up to the normal operating temperature.
2. Keep the engine speed approximately 1,000 rpm at no load.
3. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-367, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217868
1.CHECK COOLING FAN SPEED SENSOR POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Disconnect electrically-controlled c ooling fan coupling harness connector.
3. Turn ignition switch ON.
4. Check the voltage between electrically-controlled cooling fan coupling harness connector terminals.
Is inspection result normal?
YES >> GO TO 6.
NO >> GO TO 2.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0527 Cooling fan speed sen-
sor circuit range/perfor-
mance The number of fan speed signals is 16 rpm or
less during engine rev.  Harness or connectors
(The Fuel rail pressure sensor circuit is
open or shorted.)
(The Power steering pressure sensor cir-
cuit is open or shorted)
(The Electrically-controlled cooling fan
coupling circuit is open or shorted)
 Fuel rail pressure sensor
 Power steering pressure sensor
 Cooling fan speed sensor
 Electrically-controlled cooling fan cou- pling
 Cooling fan
 IPDM E/R
Electrically-controlled cooling fan coupling Vo l ta g e
(Approx.)
Connector +
−
terminal
F39 2 4 5 V
Revision: 2010 May2011 QX56

EC-368
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0527 COOLING FAN SPEED SENSOR
2.CHECK COOLING FAN SPEED SENSOR POWER SUPPLY CIRCUIT-II
1. Check the voltage between electrically-controlled cooling fan coupling 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 COOLING FAN SPEED SENSOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between electrically-contro lled cooling fan coupling harness connector and ECM har-
ness 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.
+
−Vol tag e
(Approx.)
Electrically-controlled cooling fan coupling
Connector terminalF39 2 Ground 5 V
ECM Sensor
Connector Terminal Name Connector Terminal
F 111 27Low fuel pressure sensor F25 3
Power steering pressure sensor F35 1
Cooling fan speed sensor F39 2
28 FRP sensor F26 1
+ −
Continuity
Electrically-controlled cooling fan
coupling ECM
Connector Terminal Connector Terminal F 3 9 4 F 111 4 5 E x i s t e d
Revision: 2010 May2011 QX56

P0550 PSP SENSOREC-371
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P0550 PSP SENSOR
DTC LogicINFOID:0000000006217870
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.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and let it idle for at least 5 seconds.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-371, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217871
1.CHECK POWER STEERING PRESSURE SENSOR POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Disconnect power steering pressure (PSP) sensor harness connector.
3. Turn ignition switch ON.
4. Check the voltage between PSP sensor harness connector terminals.
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 2.
2.CHECK POWER STEERING PRESSURE SENSOR POWER SUPPLY CIRCUIT-II
1. Check the voltage between PSP sensor harness connector and the ground.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0550 PW ST P SEN/CIRC
(Power steering pressure
sensor circuit) An excessively low or high voltage from the
sensor is sent to ECM.  Harness or connectors
(The Fuel rail pressure sensor circuit is
open or shorted.)
(The Power steering pressure sensor cir-
cuit is open or shorted)
(The Electrically-controlled cooling fan
coupling circuit is open or shorted)
 Fuel rail pressure sensor
 Power steering pressure sensor
 Electrically-controlled cooling fan cou- pling
PSP sensor Vo l ta g e
(Approx.)
Connector +
−
terminal
F35 1 3 5 V
Revision: 2010 May2011 QX56

EC-372
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0550 PSP 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 PSP SENSOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between PSP sens or harness connector and ECM harness connector.
4. Also check harness for short to ground and short to power.
Is the 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".
+
−Voltag e
(Approx.)
PSP sensor
Connector terminal F35 1 Ground 5 V
ECM Sensor
Connector Terminal Name Connector Terminal
F 111 27Low fuel pressure sensor F25 3
Power steering pressure sensor F35 1
Cooling fan speed sensor F39 2
28 FRP sensor F26 1
+ −
Continuity
PSP sensor ECM
Connector Terminal Connector Terminal F35 3 F111 45 Existed
+ −Continuity
ECM
Connector Terminal F 111 1 0 Ground Existed
E80 174
175
Revision: 2010 May2011 QX56

P1197 OUT OF GASEC-397
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P1197 OUT OF GAS
DescriptionINFOID:0000000006217903
This diagnosis result is detected when the fuel level
of the fuel tank is extremely low and the engine does not
run normally.
DTC LogicINFOID:0000000006217904
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-I
Start the engine.
Does the engine start?
YES >> GO TO 3.
NO >> Proceed to EC-398, "
Diagnosis Procedure".
3.PERFORM DTC CONFIRMATION PROCEDURE-II
1. Warm up the engine to the normal operating temperature. NOTE:
For best results, warm up the engine until “COOLAN TEMP/S” on “DATA MONITOR” of CONSULT-III
reaches at least 70 °C (158 °F).
2. Keep the engine speed at 3,500 rpm for 5 seconds and let it idle at least 60 seconds..
3. Check the 1st trip DTC. NOTE:
If the fuel tank has sufficient fuel, this diagnosis result may not be detected.
Is 1st trip DTC detected?
YES >> Proceed to EC-398, "Diagnosis Procedure".
NO >> INSPECTION END
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P1197 FUEL RUN OUT
(Out of gas)  Fuel rail pressure remains at 1.5 MPa (15
bar, 15.3 kg/cm
2, 217.5 psi) or less for 3
seconds or more with the fuel level too
low.
 Fuel rail pressure remains 2.7 MPa (27
bar, 27.5 kg/cm
2, 392 psi) lower than a tar-
get fuel pressure for 5 seconds or more
with the fuel level too low.
 Fuel rail pressure remains at 0.23 MPa
(2.3 bar, 2.346 kg/cm
2, 33.35 psi) or less
for 5 seconds or more with the fuel level
too low.
NOTE:
Allow engine coolant temperature to reach
70 °C (158 °F) or more once.  Out of gas
 Harness or connectors (The low pressure fuel
pump circuit is open or shorted.)
 Low pressure fuel pump
 Fuel pressure regulator
 Low pressure fuel system
 Low fuel pressure sensor
 Harness or connectors (The high pressure fuel
pump circuit is shorted.)
 High pressure fuel pump
 High pressure fuel system
 Fuel rail pressure sensor
 Disconnection of the fuel hose
Revision: 2010 May2011 QX56

EC-398
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P1197 OUT OF GAS
Diagnosis Procedure
INFOID:0000000006217905
1.REFUEL THE VEHICLE
1. Refuel 10 liter (10 US qt, 8 imp qt). CAUTION:
Never refuel more than 10 liter.
2. Start the engine and keep the engine speed at 3,000 rpm for 30 seconds. NOTE:
For best results, warm up the engine until “COOLA N TEMP/S” on “DATA MONITOR” of CONSULT-III
reaches at least 70 °C (158 °F).
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Turn ignition switch ON.
7. Erase the DTC.
8. Start the engine and let it idle at least 60 seconds.
9. Perform the confirmation procedure again. Refer to EC-397, "
DTC Logic".
Is 1st trip DTC detected?
YES >> GO TO 2.
NO >> INSPECTION END
2.CHECK LOW PRESSURE FUEL PUMP
Refer to EC-512, "
Component Function Check".
Is inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace error-detected parts.
3.CHECK HIGH PRESSURE FUEL PUMP
Refer to EC-501, "
Component Function Check".
Is inspection result normal?
YES >> Check the fuel hose for disconnection and looseness.
NO >> Repair or replace error-detected parts.
Revision: 2010 May2011 QX56

P2539, P2541, P2542 LOW FUEL PRESSURE SENSOR
EC-483
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P2539, P2541, P2542 LOW
FUEL PRESSURE SENSOR
DTC LogicINFOID: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 ProcedureINFOID: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
Vo l ta g e
(Approx.)
Connector +
−
terminal
F25 3 1 5 V
Revision: 2010 May2011 QX56