2011 INFINITI QX56 fuel pressure

EC-196
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0087, P0088, P009
0 FRP CONTROL SYSTEM
Diagnosis Procedure
INFOID:0000000006217785
1.CHECK LOW FUEL PRESSURE
WITH CONSULT-III
1. Start the engine.
2. Check “L/FUEL PRES SEN V” in “DAT A MONITOR” of “ECM” with CONSULT-III.
WITHOUT CONSULT-III
1. Start the engine.
2. Check low fuel pressure sensor signal voltage.
Is inspection result normal?
YES >> GO TO 2.
NO >> Check low fuel pressure system. Refer to EC-512, "
Diagnosis Procedure".
2.PERFORM THE HIGH PRESSURE FUEL PUMP COMPONENT INSPECTION
Perform the high pressure fuel pum p component inspection. Refer to EC-196, "
Component Inspection".
Is inspection result normal?
YES >> GO TO 3.
NO >> Replace the fuel pump.
3.CHECK FUEL LEAKAGE
1. Start the engine.
2. Visually check that the fuel pump, fuel rail, and fuel piping have no fuel leakage.
Is inspection result normal?
YES >> Check that the fuel syst em has no breakage, bend, and crush.
NO >> Repair or Replace the error-detected parts.
Component InspectionINFOID:0000000006217786
1.CHECK HIGH PRESSURE FUEL PUMP-I
1. Turn ignition switch OFF.
2. Disconnect high pressure fuel pump harness connector.
3. Check the resistance between high pressure fuel pump terminals as follows.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace high pressure fuel pump. Refer to EM-49, "
Removal and Installation".
Data monitor item Condition Va l u e
(Approx.)
L/FUEL PRES SEN V Engine speed: idle
3,000 –3,300 mV
Engine speed: 3,000 rpm (no load)
+ −Condition Va l u e
(Approx.)
Low fuel pressure sensor
Connector Terminal
F25 2 Ground Engine speed: idle
3.0 –3.3 V
Engine speed: 3,000 rpm (no load)
+ −
Condition Resistance
High pressure fuel pump
Te r m i n a l
1 2 Temperature °C ( °F) 20 – 30 (68 - 86) 9 - 11 Ω
Revision: 2010 May2011 QX56

P0087, P0088, P0090 FRP CONTROL SYSTEM
EC-197
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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2.CHECK HIGH PRESSURE FUEL PUMP-II
WITH CONSULT-III
1. Reconnect high pressure fuel pump harness connector.
2. Start the engine.
3. Check “FUEL PRES SEN” in “DATA MONITOR” of “ECM” with CONSULT-III.
WITHOUT CONSULT-III
1. Start the engine.
2. Check fuel rail pressure sensor signal voltage.
YES >> INSPECTION END
NO >> Replace high pressure fuel pump. Refer to EM-43, "
Removal and Installation".
Data monitor item Condition Vo l ta g e
(Approx.)
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 Va l u e
(Approx.)
Fuel rail pressure sensor
Connector Terminal
F26 2 Ground Engine speed: idle 0.98 – 1.2 V
Engine speed: Revving engine from idle to 4,000 rpm quickly 1.1 – 2.9 V
Revision: 2010 May2011 QX56

EC-198
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P008A LOW FUEL PRESSURE CONTROL SYSTEM
P008A LOW FUEL PRESSURE CONTROL SYSTEM
DTC LogicINFOID:0000000006217787
DTC DETECTION LOGIC
NOTE:
If DTC P008A is displayed with DTC P1197, first pe
rform the trouble diagnosis for DTC P1197. Refer to
EC-397, "
DTC 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. Check that the fuel tank is 1/8 full of fuel.
2. Start the engine and warm it up to the normal operating temperature. NOTE:
When replacing ECM, warm up the engine until “C OOLAN TEMP/S” on “DATA MONITOR” of CONSULT-
III reaches at least 70 °C (158 °F).
3. Let the engine at idle for 60 seconds.
4. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-398, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217788
1.PERFORM LOW PRESSURE FUEL PUMP COMPONENT FUNCTION CHECK
Refer to EC-512, "
Component Function Check".
Is the inspection result normal?
YES >> GO TO 2.
NO >> Perform low pressure fuel pump diagnosis. Refer to EC-512, "
Diagnosis Procedure".
2.CHECK FUEL LEAKAGE
1. Start the engine.
2. Visually check that the low fuel pressure system has no fuel leakage.
Is inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace error-detected parts.
3.CHECK LOW PRESSURE FUEL PIPING AND HOSE
1. Turn ignition switch OFF.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P008A Low fuel pressure too low A condition of low fuel pressure 0.23
MPa (2.3 bar, 2.346 kg/cm
2, 33.35 psi)
or less continues for 5 seconds or more
after warming up the engine.  Harness or connectors
(The low pressure fuel pump circuit is
open or shorted.)
 Low pressure fuel pump
 Fuel pressure regulator
 Low pressure fuel system
 Out of gas
Revision: 2010 May2011 QX56

P008A LOW FUEL PRESSURE CONTROL SYSTEMEC-199
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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2. Check that the low pressure fuel piping and hose have no breakage, bend, and crush. Refer to
FL-4,
"Inspection".
Is inspection result normal?
YES >> Replace fuel level sensor unit and fuel pump (fuel pressure regulator malfunction). Refer to FL-5,
"Removal and Installation".
NO >> Repair or replace error-detected parts.
Revision: 2010 May2011 QX56

EC-200
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P008B LOW FUEL PRESSURE CONTROL SYSTEM
P008B LOW FUEL PRESSURE CONTROL SYSTEM
DTC LogicINFOID:0000000006288272
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next test.
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 keep the engine speed at idle for 60 seconds.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-200, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288273
1.CHECK FUEL PUMP CONTROL MODULE (FPCM) SIGNAL
Refer to EC-405, "
Component Inspection (FPCM)".
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace FPCM. Refer to EC-537, "
Removal and Installation".
2.CHECK FUEL PUMP CONTROL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect FPCM harness connector and fuel level sensor unit and fuel pump harness connector.
3. Check the continuity between FPCM harness connecto r and fuel level sensor unit and fuel pump harness
connector.
4. Also check harness for short to ground and short to power.
Is inspection result normal?
YES >> Replace fuel level sensor unit and fuel pump (fuel pressure regulator malfunction). Refer to FL-5,
"Removal and Installation".
NO >> Repair or replace error-detected parts.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P008B Low fuel pressure too high A condition of low fuel pressure 0.67
MPa (6.7 bar, 6.834 kg/cm
2, 97.15 psi)
or more continues for 5 seconds or
more after warming up the engine.  Harness or connectors
(The low pressure fuel pump circuit is
open or shorted.)
 Fuel pressure regulator
FPCM Fuel level sensor unit and fuel pump Continuity
Connector Terminal Connector Terminal
B41 6
C5 3
Existed
71
Revision: 2010 May2011 QX56

EC-238
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0133, P0153 A/F SENSOR 1
P0133, P0153 A/F SENSOR 1
DTC LogicINFOID:0000000006217811
DTC DETECTION LOGIC
To judge the malfunction of A/F sensor
1, this diagnosis measures response time of the A/F signal computed
by ECM from the A/F sensor 1 signal. The time is compensated by engine operating (speed and load), fuel
feedback control constant, and the A/F sensor 1 temper ature index. Judgment is based on whether the com-
pensated time (the A/F signal cycling time index) is inordinately long or not.
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.
Will CONSULT-III be used?
YES >> GO TO 2.
NO >> GO TO 5.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Restart engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
6. Let engine idle for 1 minute.
7. Select “A/F SEN1(B1) P1278/P1279” (for DTC P 0133) or “A/F SEN1(B2) P1288/P1289” (for DTC P0153)
of “A/F SEN1” in “DTC WORK SUPPORT” mode with CONSULT-III.
8. Touch “START”.
Is
“COMPLETED” displayed on CONSULT-III screen?
YES >> GO TO 3
NO >> GO TO 4.
3.PERFORM DTC CONFIRMATION PROCEDURE-II
Touch “SELF-DIAG RESULT”.
Which is displayed on CONSULT-III screen?
OK >> INSPECTION END
NG >> Go to EC-239, "
Diagnosis Procedure".
4.PERFORM DTC CONFIRMATION PROCEDURE-II
DTC No.Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible Cause
P0133 A/F SENSOR1 (B1)
[Air fuel ratio (A/F) sensor 1
(bank 1) circuit slow response]
 The response of the A/F signal computed by ECM from A/F sensor 1 signal takes
more than the specified time.  Harness or connectors
(The A/F sensor 1 circuit is open or
shorted.)
 A/F sensor 1
 A/F sensor 1 heater
 Fuel pressure
 Fuel injector
 Intake air leaks
 Exhaust gas leaks
PCV
 Mass air flow sensor
P0153
A/F SENSOR1 (B2)
[Air fuel ratio (A/F) sensor 1
(bank 2) circuit slow response]
Revision: 2010 May2011 QX56

P0133, P0153 A/F SENSOR 1EC-239
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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1. After perform the following procedure, “TESTIN
G” will be displayed on the CONSULT-III screen.
- Increase the engine speed up to between 4,000 and 5,000 rpm and maintain that speed for 10 seconds.
- Fully release accelerator pedal and then let engine idle for approximately 10 seconds. If “TESTING” is not displayed after 10 seconds, refer to EC-161, "
Component Function Check".
2. Wait for approximately 20 seconds at idle under t he condition that “TESTING” is displayed on the CON-
SULT-III screen.
3. Check that “TESTING” changes to “COMPLETED”. If “TESTING” changed to “OUT OF CONDITION”, refer to EC-161, "
Component Function Check".
4. Touch “SELF-DIAG RESULT”.
Which is displayed on CONSULT-III screen?
OK >> INSPECTION END
NG >> Go to EC-239, "
Diagnosis Procedure".
5.CHECK AIR-FUEL RATIO SELF-LEARNING VALUE
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Select Service $01 with GST.
3. Calculate the total value of “Short term f uel trim” and “Long term fuel trim” indications.
Is the total percentage within
±15%?
YES >> GO TO 7.
NO >> GO TO 6.
6.DETECT MALFUNCTIONING PART
Check the following.
 Intake air leaks
 Exhaust gas leaks
 Incorrect fuel pressure
 Lack of fuel
 Fuel injector
 Incorrect PCV hose connection
PCV valve
 Mass air flow sensor
>> Repair or replace malfunctioning part.
7.PERFORM DTC CONFIRMATION PROCEDURE
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
3. Let engine idle for 1 minute.
4. Increase the engine speed up to between 4,000 and 5,000 rpm and maintain that speed for 10 seconds.
5. Fully release accelerator pedal and then let engine idle for approximately 1 minute.
6. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-239, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217812
1.RETIGHTEN AIR FUEL RATIO SENSOR 1
Loosen and retighten the air fuel rati o (A/F) sensor 1. Refer to EM-40, "
Exploded View".
>> GO TO 2.
2.CHECK EXHAUST GAS LEAKAGE
1. Start engine and run it at idle.
Revision: 2010 May2011 QX56

P0137, P0157 HO2S2EC-243
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P0137, P0157 HO2S2
DTC LogicINFOID:0000000006217813
DTC DETECTION LOGIC
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the air fuel
ratio (A/F) sensor 1. The oxy-
gen storage capacity of the three way catalyst (manifold) causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the maximum voltage of the sensor
is sufficiently high during various driving conditions such as fuel cut.
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.
Will CONSULT-III be used?
YES >> GO TO 2.
NO >> GO TO 4.
2.PERFORM DTC CONFIRMATION PROCEDURE
WITH CONSULT-III
TESTING CONDITION:
For better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30 °C (32 to 86 °F).
1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Turn ignition switch ON.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Restart engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
6. Let engine idle for 1 minute.
7. Select “DATA MONITOR” mode with CONSULT-III.
8. Check that “COOLAN TEMP/S” indicates more than 70 °C (158 °F).
If not, warm up engine and go to next step w hen “COOLAN TEMP/S” indication reaches 70 °C (158 °F).
9. Open engine hood.
10. Select “HO2S2 (B1) P1147” (for DTC P0137) or “HO2S2 (B2) P1167” (for DTC P0157) of “HO2S2” in
“DTC WORK SUPPORT” mode with CONSULT-III.
11. Follow the instruction of CONSULT-III display.
NOTE:
It will take at most 10 minutes until “COMPLETED” is displayed.
12. Touch “SELF-DIAG RESULTS”.
JMBIA1572GB
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0137 HO2S2 (B1)
[Heated oxygen sensor 2
(bank 1) circuit low voltage]
The maximum voltage from the sensor does
not reach the specified voltage.  Harness or connectors
(The heated oxygen sensor 2 circuit is
open or shorted)
 Heated oxygen sensor 2
 Fuel pressure
 Fuel injector
 Intake air leaks
P0157
HO2S2 (B2)
[Heated oxygen sensor 2
(bank 2) circuit low voltage]
Revision: 2010 May2011 QX56