2011 INFINITI QX56 air condition

P0125 ECT SENSOREC-223
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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NO >> Replace engine coolant temperature sensor.
2.CHECK THERMOSTAT OPERATION
When the engine is cold [lower than 70 °C (158 °F)] condition, grasp lower radiator hose and confirm that the
engine coolant does not flow.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace thermostat. Refer to CO-20, "
Removal and Installation".
3.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
Component Inspection (Engine Coolant Temperature Sensor)INFOID:0000000006288610
1.CHECK ENGINE COOLANT TEMPERATURE SENSOR
1. Turn ignition switch OFF.
2. Disconnect engine coolant temperature sensor harness connector.
3. Remove engine coolant temperature sensor.
4. Check resistance between engine coolant temperature sensor
terminals by heating with hot water as shown in the figure.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace engine coolant temperature sensor. Refer to EM-86, "
Exploded View".
Terminals Condition Resistance (k Ω)
1 and 2 Temperature [ °C ( °F)] 20 (68) 2.35 - 2.73
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
JMBIA0080ZZ
Revision: 2010 May2011 QX56

EC-224
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0127 IAT SENSOR
P0127 IAT SENSOR
DTC LogicINFOID:0000000006288283
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:
This test may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road
test is expected to be easier, it is unnecessary to lift the vehicle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
WITH CONSULT-III
1. Wait until engine coolant temperature is less than 90 °C (194 °F)
- Turn ignition switch ON.
- Select “DATA MONITOR” mode with CONSULT-III.
- Check the engine coolant temperature.
- If the engine coolant temperature is not less than 90 °C (194 °F), turn ignition switch OFF and cool down
engine.
NOTE:
Perform the following steps before engine coolant temperature is above 90 °C (194 °F).
2. Turn ignition switch ON.
3. Select “DATA MONITOR” mode with CONSULT-III.
4. Start engine.
5. Hold vehicle speed at more than 70 km/h (43 MPH) for 100 consecutive seconds.
CAUTION:
Always drive vehicle at a safe speed.
6. Check 1st trip DTC.
WITH GST
Follow the procedure “With CONSULT-III” above.
Is 1st trip DTC detected?
YES >> Proceed to EC-224, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288284
1.CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to EC-225, "
Component Inspection (Intake Air Temperature Sensor)".
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace mass air flow sensor (with intake air temperature sensor).
2.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0127 IAT SENSOR-B1
(Intake air temperature too
high) Rationally incorrect voltage from the sensor is
sent to ECM, compared with the voltage signal
from engine coolant temperature sensor.  Harness or connectors
(The intake air temperature sensor
circuit is open or shorted)
 Intake air temperature sensor
Revision: 2010 May2011 QX56

P0127 IAT SENSOREC-225
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>> INSPECTION END
Component Inspection (Intak
e Air Temperature Sensor)INFOID:0000000006288285
1.CHECK INTAKE AIR TEMPERATURE SENSOR
1. Turn ignition switch OFF.
2. Disconnect mass air flow sensor harness connector.
3. Check resistance between mass air flow s ensor terminals as per the following.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace mass air flow sensor (with intake air temperature sensor). Refer to EM-30, "
Removal and
Installation".
Terminals Condition Resistance (kΩ)
1 and 2 Temperature [ °C ( °F)] 25 (77) 1.94 - 2.06
Revision: 2010 May2011 QX56

EC-228
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0130, P0150 A/F SENSOR 1
P0130, P0150 A/F SENSOR 1
DTC LogicINFOID:0000000006217804
DTC DETECTION LOGIC
To judge malfunctions, the diagnosis checks that the A/
F signal computed by ECM from the A/F sensor 1 sig-
nal fluctuates according to fuel feedback control.
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 FOR MALFUNCTION A
1. Start engine and warm it up to normal operating temperature.
2. Let engine idle for 2 minutes.
3. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-230, "Diagnosis Procedure".
NO-1 >> With CONSULT-III: GO TO 3.
NO-2 >> With GST: GO TO 7.
3.CHECK AIR FUEL RATIO (A/F) SENSOR 1 FUNCTION
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Select “A/F SEN1 (B1)” or “A/F SEN1 (B 2)” in “DATA MONITOR” mode with CONSULT-III.
3. Check “A/F SEN1 (B1)” or “A/F SEN1 (B2)” indication.
Does the indication fluctuate around 1.5 V?
YES >> GO TO 4.
NO >> Go to EC-230, "
Diagnosis Procedure".
4.PERFORM DTC CONFIRMATION PR OCEDURE FOR MALFUNCTION B-I
1. Select “A/F SEN1 (B1) P1276” (for DTC P0130) or “A/F SEN1 (B2) P1286” (for DTC P0150) of “A/F
SEN1” in “DTC WORK SUPPORT” mode with CONSULT-III.
2. Touch “START”.
3. When the following conditions are met, “T ESTING” will be displayed on the CONSULT-III screen.
DTC No.Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible Cause
P0130 A/F SENSOR1 (B1)
[Air fuel ratio (A/F) sensor 1
(bank 1) circuit] A)
The A/F signal computed by ECM from the A/F
sensor 1 signal is constantly in a range other
than approx. 1.5 V.
 Harness or connectors(The A/F sensor 1 circuit is open
or shorted.)
 A/F sensor 1
B)
The A/F signal computed by ECM from the A/F
sensor 1 signal is constantly approx. 1.5 V.
P0150 A/F SENSOR1 (B2)
[Air fuel ratio (A/F) sensor 1
(bank 2) circuit] A)
The A/F signal computed by ECM from the A/F
sensor 1 signal is constantly in a range other
than approx. 1.5 V.
B) The A/F signal computed by ECM from the A/F
sensor 1 signal is constantly approx. 1.5 V.
Revision: 2010 May2011 QX56

EC-232
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0131, P0151 A/F SENSOR 1
P0131, P0151 A/F SENSOR 1
DTC LogicINFOID:0000000006217807
DTC DETECTION LOGIC
To judge the malfunction, the diagnosis checks that t
he A/F signal computed by ECM from the A/F sensor 1
signal is not inordinately low.
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 10.5 V or more at idle.
>> GO TO 2.
2.CHECK A/F SENSOR FUNCTION
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Select “A/F SEN1 (B1)” or “A/F SEN1 (B 2)” in “DATA MONITOR” mode with CONSULT-III.
3. Check “A/F SEN1 (B1)” or “A/F SEN1 (B2)” indication.
WITH GST
Follow the procedure “With CONSULT-III” above.
Is the indication constantly approx. 0 V?
YES >> Go to EC-233, "Diagnosis Procedure".
NO >> GO TO 3.
3.PERFORM DTC CONFIRMATION PROCEDURE
WITH CONSULT-III
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.
4. Restart engine.
5. Drive and accelerate vehicle to more than 40 km/h (25 MPH) within 20 seconds after restarting engine.
CAUTION:
Always drive vehicle at a safe speed.
6. Maintain the following conditions fo r approximately 20 consecutive seconds.
NOTE:
 Keep the accelerator pedal as stead y as possible during cruising.
DTC No.Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible Cause
P0131 A/F SENSOR1 (B1)
[Air fuel ratio (A/F) sensor 1
(bank 1) circuit low voltage]
 The A/F signal computed by ECM from the A/F
sensor 1 signal is constantly approx. 0 V.  Harness or connectors
(The A/F sensor 1 circuit is open or
shorted.)
 A/F sensor 1
P0151 A/F SENSOR1 (B2)
[Air fuel ratio (A/F) sensor 1
(bank 2) circuit low voltage]
ENG SPEED 1,000 - 3,200 rpm
VHCL SPEED SE More th
an 40 km/h (25 mph)
B/FUEL SCHDL 1.5 - 9.0 msec
Selector lever Suitable position
Revision: 2010 May2011 QX56

P0132, P0152 A/F SENSOR 1EC-235
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P0132, P0152 A/F SENSOR 1
DTC LogicINFOID:0000000006217809
DTC DETECTION LOGIC
To judge the malfunction, the diagnosis checks that the
A/F signal computed by ECM from the A/F sensor 1
signal is not inordinately high.
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 10.5 V or more at idle.
>> GO TO 2.
2.CHECK A/F SENSOR FUNCTION
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Select “A/F SEN1 (B1)” or “A/F SEN1 (B2) ” in “DATA MONITOR” mode with CONSULT-III.
3. Check “A/F SEN1 (B1)” or “A/F SEN1 (B2)” indication.
WITH GST
Follow the procedure “With CONSULT-III” above.
Is the indication constantly approx. 5 V?
YES >> Go to EC-236, "Diagnosis Procedure".
NO >> GO TO 3.
3.PERFORM DTC CONFIRMATION PROCEDURE
WITH CONSULT-III
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.
4. Restart engine.
5. Drive and accelerate vehicle to more than 40 km/h (25 MPH) within 20 seconds after restarting engine. CAUTION:
Always drive vehicle at a safe speed.
6. Maintain the following conditions for approximately 20 consecutive seconds.
NOTE:
Keep the accelerator pedal as steady as possible during cruising.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible Cause
P0132 A/F SENSOR1 (B1)
[Air fuel ratio (A/F) sensor 1
(bank 1) circuit high voltage]
 The A/F signal computed by ECM from the
A/F sensor 1 signal is constantly approx. 5 V.  Harness or connectors
(The A/F sensor 1 circuit is open or
shorted.)
 A/F sensor 1
P0152 A/F SENSOR1 (B2)
[Air fuel ratio (A/F) sensor 1
(bank 2) circuit high voltage]
ENG SPEED 1,000 - 3,200 rpm
VHCL SPEED SE More than 40 km/h (25 mph)
B/FUEL SCHDL 1.5 - 9.0 msec
Selector lever Suitable position
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