2011 INFINITI QX56 fuel cap

P0138, P0158 HO2S2EC-249
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
P0138, P0158 HO2S2
DTC LogicINFOID:0000000006217817
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 oxygen storage capacity of the thr ee way catalyst (manifold) causes the longer switching
time.
MALFUNCTION A
To judge the malfunctions of heated oxygen sensor 2, ECM monitors
whether the voltage is unusually high during various driving condi-
tions such as fuel cut.
MALFUNCTION B
To judge the malfunctions of heated oxygen sensor 2, ECM monitors
whether the minimum voltage of sensor is sufficiently low during var-
ious driving conditions such as fuel cut.
DTC CONFIRMATION PROCEDURE
PBIB1848E
PBIB2376E
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0138 HO2S2 (B1)
[Heated oxygen sensor 2
(bank 1) circuit high voltage] A)
An excessively high voltage from the
sensor is sent to ECM.  Harness or connectors
(The heated oxygen sensor 2 circuit is
open or shorted)
 Heated oxygen sensor 2
B) The minimum voltage from the sensor is
not reached to the specified voltage.  Harness or connectors
(The heated oxygen sensor 2 circuit is
open or shorted)
 Heated oxygen sensor 2
 Fuel pressure
 Fuel injector
P0158 HO2S2 (B2)
[Heated oxygen sensor 2
(bank 2) circuit high voltage] A)
An excessively high voltage from the
sensor is sent to ECM.  Harness or connectors
(The heated oxygen sensor 2 circuit is
open or shorted)
 Heated oxygen sensor 2
B) The minimum voltage from the sensor is
not reached to the specified voltage.  Harness or connectors
(The heated oxygen sensor 2 circuit is
open or shorted)
 Heated oxygen sensor 2
 Fuel pressure
 Fuel injector
Revision: 2010 May2011 QX56

P0139, P0159 HO2S2EC-257
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
P0139, P0159 HO2S2
DTC LogicINFOID:0000000006217821
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 switching response of the sen-
sor's voltage is faster than specified 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 when “COOLAN TEMP/S” indication reaches to 70°C (158 °F).
9. Open engine hood.
10. Select “HO2S2 (B1) P0139” or “HO2S2 (B2) P 0159” of “HO2S2” in “DTC WORK SUPPORT” mode with
CONSULT-III.
11. Start engine and follow the instruction of CONSULT-III display.
NOTE:
It will take at most 10 minutes until “COMPLETED” is displayed.
12. Touch “SELF-DIAG RESULTS”.
SEF302U
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0139 HO2S2 (B1)
[Heated oxygen sensor 2
(bank 1) circuit slow response] It takes more time for the sensor to respond
between rich and lean than the specified
time.  Harness or connectors
(The heated oxygen sensor 2 circuit is
open or shorted)
 Heated oxygen sensor 2
 Fuel pressure
 Fuel injector
 Intake air leaks
P0159
HO2S2 (B2)
[Heated oxygen sensor 2
(bank 2) circuit slow response]
Revision: 2010 May2011 QX56

P0420, P0430 THREE WAY CATALYST FUNCTIONEC-307
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
P0420, P0430 THREE WAY CATALYST FUNCTION
DTC LogicINFOID:0000000006217851
DTC DETECTION LOGIC
The ECM monitors the switching frequency ratio of air fuel ratio (A/F)
sensor 1 and heated oxygen sensor 2.
A three way catalyst (manifold) with high oxygen storage capacity
will indicate a low switching frequency of heated oxygen sensor 2.
As oxygen storage capacity decr
eases, the heated oxygen sensor 2
switching frequency will increase.
When the frequency ratio of A/F sensor 1 and heated oxygen sensor
2 approaches a specified limit value, the three way catalyst (mani-
fold) malfunction is diagnosed.
DTC CONFIRMATION PROCEDURE
1.INSPECTION START
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 6.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
WITH CONSULT-III
TESTING CONDITION:
Do not maintain engine speed for mo re than the specified minutes below.
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. Start 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 when “COOLAN TEMP/S” indication reaches to 70°C (158 °F).
9. Open engine hood.
10. Select “DTC & SRT CONFIRMATION” then “SRT WORK SUPPORT” mode with CONSULT-III.
11. Rev engine between 2,000 and 3,000 rpm and hold it for 3 consecutive minutes then release the acceler-
ator pedal completely.
12. Check the indication of “CATALYST”.
Which is displayed on CONSULT-III screen?
CMPLT >> GO TO 5.
INCMP >> GO TO 3.
PBIB2055E
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0420 TW CATALYST SYS-B1
[Catalyst system efficiency
below threshold (bank 1)]
 Three way catalyst (manifold) does not
operate properly.
 Three way catalyst (manifold) does not have enough oxygen storage capacity.  Three way catalyst (manifold)
 Exhaust tube
 Intake air leakage
 Fuel injector
 Fuel injector leakage
 Spark plug
 Improper ignition timing
P0430
TW CATALYST SYS-B2
[Catalyst system efficiency
below threshold (bank 2)]
Revision: 2010 May2011 QX56

EC-346
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0456 EVAP CONTROL SYSTEM
P0456 EVAP CONTROL SYSTEM
DTC LogicINFOID:0000000006288325
DTC DETECTION LOGIC
This diagnosis detects leaks in the EVAP line between f
uel tank and EVAP canister purge volume control sole-
noid valve, using the negative pressure caused by decrease of fuel temperature in the fuel tank after turning
ignition switch OFF.
If ECM judges there are no leaks, the diagnosis will be OK.
CAUTION:
 Use only a genuine NISSAN fuel filler cap as a replacemen t. If an incorrect fuel filler cap is used, the
MIL may illuminate.
 If the fuel filler cap is not tightened properly, the MIL may illuminate.
 Use only a genuine NISSAN rubber tube as a replacement.
DTC CONFIRMATION PROCEDURE
PBIB1026E
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0456 Evaporative emission control
system leak  EVAP system has a leak.
 EVAP system does not op-
erate properly.  Incorrect fuel tank vacuum relief valve
 Incorrect fuel filler cap used
 Fuel filler cap remains open or does not close.
 Foreign matter caught in fuel filler cap.
 Leak is in line between intake manifold and EVAP canis-
ter purge volume control solenoid valve.
 Foreign matter caught in EVAP canister vent control valve.
 EVAP canister or fuel tank leaks
 EVAP purge line (pipe and rubber tube) leaks
 EVAP purge line rubber tube bent
 Loose or disconnected rubber tube
 EVAP canister vent control valve and the circuit
 EVAP canister purge volume control solenoid valve and the circuit
 Fuel tank temperature sensor
 O-ring of EVAP canister vent control valve is missing or damaged
 EVAP canister is saturated with water
 EVAP control system pressure sensor
 Refueling EVAP vapor cut valve
 ORVR system leaks
 Fuel level sensor and the circuit
 Foreign matter caught in EVAP canister purge volume control solenoid valve
Revision: 2010 May2011 QX56

P0456 EVAP CONTROL SYSTEMEC-347
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
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.
Do you have CONSULT-III?
YES >> GO TO 2.
NO >> GO TO 4.
2.PERFORM DTC CONFIRMATION PROCEDURE-I
WITH CONSULT-III
1. Turn ignition switch ON and select “EVAP DIAG READY” in “DATA MONITOR” mode with CONSULT-III.
2. Start engine and wait at idle until “OFF” of “EVAP DIAG READY” changes to “ON”.
NOTE:
It will take at most 2 hours until “OFF” of “EVAP DIAG READY” changes to “ON”.
3. Turn ignition switch OFF and wait at least 90 minutes. NOTE:
Never turn ignition swit ch ON during 90 minutes.
4. Turn ignition switch ON and select “EVAP LEAK DIAG” in “DATA MONITOR” mode with CONSULT-III.
5. Check that “EVAP LEAK DIAG” indication.
Which is displayed on CONSULT-III?
CMPLT >> GO TO 3.
YET >> Perform DTC CONFIRMATION PROCEDURE again. GO TO 1.
3.PERFORM DTC CONFIRMATION PROCEDURE-II
Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-347, "Diagnosis Procedure".
NO >> INSPECTION END.
4.PERFORM DTC CONFIRMATION PROCEDURE
WITH GST
1. Start engine and wait engine idle for at least 2 hours.
2. Turn ignition switch OFF and wait at least 90 minutes.
NOTE:
Never turn ignition swit ch ON during 90 minutes.
3. Turn ignition switch ON.
4. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-347, "Diagnosis Procedure".
NO >> INSPECTION END.
Diagnosis ProcedureINFOID:0000000006288326
1.CHECK FUEL FILLER CAP DESIGN
1. Turn ignition switch OFF.
2. Check for genuine NISSAN fuel filler cap design.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace with genuine NISSAN fuel filler cap.
SEF915U
Revision: 2010 May2011 QX56

EC-348
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0456 EVAP CONTROL SYSTEM
2.CHECK FUEL FILLER CAP INSTALLATION
Check that the cap is tightened proper ly by rotating the cap clockwise.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Open fuel filler cap, then clean cap and fuel filler neck threads using air blower. Then retighten until reteaching sound is heard.
3.CHECK FUEL FILLER CAP FUNCTION
Check for air releasing sound while opening the fuel filler cap.
Is the inspection result normal?
YES >> GO TO 5.
NO >> GO TO 4.
4.CHECK FUEL TANK VACUUM RELIEF VALVE
Refer to EC-350, "
Component Inspection (Fuel Filler Cap)".
Is the inspection result normal?
YES >> GO TO 5.
NO >> Replace fuel filler cap with a genuine one.
5.CHECK FOR EVAP LEAK
Refer to FL-12, "
Inspection".
Is there any leak in EVAP line?
YES >> Repair or replace.
NO >> GO TO 6.
6.CHECK EVAP CANISTER VENT CONTROL VALVE
Check the following.
 EVAP canister vent control valve is installed properly. Refer to FL-10, "
Exploded View".
 EVAP canister vent control valve. Refer to EC-327, "
Component Inspection (EVAP Cani ster Vent Control Valve)".
Is the inspection result normal?
YES >> GO TO 7.
NO >> Repair or replace EVAP canister vent control valve and O-ring. Refer to FL-10, "
Exploded View".
7.CHECK IF EVAP CANISTER SATURATED WITH WATER
1. Remove EVAP canister (1) with EVAP canister vent control valve (2) and EVAP control system pressure sensor attached.
2. Check if water will drain from the EVAP canister.
Does water drain from EVAP canister?
YES >> GO TO 8.
NO-1 >> With CONSULT-III: GO TO 10.
NO-2 >> Without CONSULT-III: GO TO 11.
8.CHECK EVAP CANISTER
Weigh the EVAP canister assembly with the EVAP canister vent control valve and EVAP control system pres-
sure sensor attached. Refer to FL-10, "
Exploded View".
The weight should be less than 2.5 kg (5.5 lb).
Is the inspection result normal?
YES-1 >> With CONSULT-III: GO TO 10.
YES-2 >> Without CONSULT-III: GO TO 11.
NO >> GO TO 9.
JSBIA0692ZZ
Revision: 2010 May2011 QX56

EC-350
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0456 EVAP CONTROL SYSTEM
NO >> Replace EVAP control system pressure sensor. Refer to
EC-335, "Component Inspection (EVAP
Control System Pressure Sensor)".
16.CHECK EVAP PURGE LINE
Check EVAP purge line (pipe, rubber tube, fuel tank and EVAP canister) for cracks or improper connection.
Refer to FL-10, "
Hydraulic Layout".
Is the inspection result normal?
YES >> GO TO 17.
NO >> Repair or reconnect the hose.
17.CLEAN EVAP PURGE LINE
Clean EVAP purge line (pipe and rubber tube) using air blower.
>> GO TO 18.
18.CHECK EVAP/ORVR LINE
Check EVAP/ORVR line between EVAP canister and fuel tank for clogging, kink, looseness and improper con-
nection. For location, refer to FL-10, "
Hydraulic Layout".
Is the inspection result normal?
YES >> GO TO 19.
NO >> Repair or replace hoses and tubes.
19.CHECK RECIRCULATION LINE
Check recirculation line between fuel filler tube and fuel tank for clogging, kink, cracks, looseness and
improper connection.
Is the inspection result normal?
YES >> GO TO 20.
NO >> Repair or replace hose, tube or fuel filler tube. Refer to FL-8, "
Exploded View".
20.CHECK REFUELING EVAP VAPOR CUT VALVE
Refer to EC-518, "
Component Inspection (EVAP Vapor Cut Valve)".
Is the inspection result normal?
YES >> GO TO 21.
NO >> Replace refueling EVAP vapor cut valve with fuel tank. Refer to FL-10, "
Exploded View".
21.CHECK FUEL LEVEL SENSOR
Refer to MWI-70, "
Component Inspection".
Is the inspection result normal?
YES >> GO TO 22.
NO >> Replace fuel level sensor unit. Refer to FL-5, "
Removal and Installation".
22.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
Component Inspection (Fuel Filler Cap)INFOID:0000000006288327
1.CHECK FUEL FILLER CAP
1. Turn ignition switch OFF.
2. Remove fuel filler cap.
Revision: 2010 May2011 QX56

P0456 EVAP CONTROL SYSTEMEC-351
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
3. Wipe clean valve housing.
4. Install fuel filler cap adapter (commercial service tool) to fuel
filler cap.
5. Check valve opening pressure and vacuum.
Is the inspection result normal?
YES >> INSPECTION END
NO >> GO TO 2.
2.REPLACE FUEL FILLER CAP
Replace fuel filler cap.
CAUTION:
Use only a genuine fuel filler cap as a replacement. If an incorrect fuel filler cap is used, the MIL may
illuminate.
>> INSPECTION END
SEF445Y
Pressure: 15.3 - 20.0 kPa (0.156 - 0.204 kg/cm2, 2.22 -
2.90 psi)
Vacuum: −6.0 to −3.3 kPa ( −0.061 to −0.034 kg/cm
2,
− 0.87 to −0.48 psi)
SEF943S
Revision: 2010 May2011 QX56