2011 INFINITI QX56 ESP

P0139, P0159 HO2S2EC-257
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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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

EC-264
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
NO >> GO TO 5.
5.PERFORM DTC CONFIRMATION PROCEDURE-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. Start engine.
5. Maintain the following conditions for at least 10 consecutive minutes. Hold the accelerator pedal as steady as possible.
CAUTION:
Always drive vehicle at a safe speed.
6. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-264, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217826
1.CHECK EXHAUST GAS LEAKAGE
1. Start engine and run it at idle.
2. Listen for an exhaust gas leakage before three way catalyst (manifold).
Is exhaust gas leakage detected?
YES >> Repair or replace malfunctioning part.
NO >> GO TO 2.
2.CHECK FOR INTAKE AIR LEAKAGE
1. Listen for an intake air leakage after the mass air flow sensor.
2. Check PCV hose connection.
Is intake air leakage detected?
YES >> Repair or replace malfunctioning part.
NO >> GO TO 3.
3.CHECK A/F SENSOR 1 CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect corresponding A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
Vehicle speed 50 - 120 km/h (31 - 75 MPH)
PBIB1216E
Revision: 2010 May2011 QX56

EC-268
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
5.PERFORM DTC CONFIRMATION PROCEDURE-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. Start engine.
5. Maintain the following conditions for at least 10 consecutive minutes. Hold the accelerator pedal as steady as possible.
CAUTION:
Always drive vehicle at a safe speed.
6. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-268, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217828
1.CHECK EXHAUST GAS LEAKAGE
1. Start engine and run it at idle.
2. Listen for an exhaust gas leakage before three way catalyst (manifold).
Is exhaust gas leakage detected?
YES >> Repair or replace malfunctioning part.
NO >> GO TO 2.
2.CHECK FOR INTAKE AIR LEAKAGE
Listen for an intake air leakage after the mass air flow sensor.
Is intake air leakage detected?
YES >> Repair or replace malfunctioning part.
NO >> GO TO 3.
3.CHECK A/F SENSOR 1 CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect corresponding A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
Vehicle speed 50 - 120 km/h (31 - 75 MPH)
PBIB1216E
Revision: 2010 May2011 QX56

EC-396
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P1148, P1168 CLOSED LOOP CONTROL
P1148, P1168 CLOSED LOOP CONTROL
DTC LogicINFOID:0000000006288347
DTC DETECTION LOGIC
NOTE:
DTC P1148 or P1168 is displayed with DTC for A/F sensor 1.
When the DTC is detected, perform the trouble di
agnosis of DTC corresponding to A/F sensor 1.
Diagnosis ProcedureINFOID:0000000006288348
DTC P1148 or P1168 is displayed with DTC for A/F sensor 1.
When the DTC is detected, perform the trouble diagnosis of DTC corresponding to A/F sensor 1.Refer to EC-
98, "DTC Index".
DTC No.Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P1148 CLOSED LOOP-B1
[Closed loop control function
(bank 1)] The closed loop control function for bank 1
does not operate even when vehicle is being
driven in the specified condition.
 Harness or connectors
(The A/F sensor 1 circuit is open or
shorted.)
 A/F sensor 1
 A/F sensor 1 heater
P1168 CLOSED LOOP-B2
[Closed loop control function
(bank 2)] The closed loop control function for bank 2
does not operate even when vehicle is being
driven in the specified condition.
Revision: 2010 May2011 QX56

EC-444
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P1572 ICC BRAKE SWITCH
Always drive vehicle at a safe speed.
NOTE:
This procedure may be conducted with the drive wheel
s 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.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-444, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217948
1.CHECK DTC WITH ADAS CONTROL UNIT
Refer to DAS-21, "
CONSULT-III Function (ICC/ADAS)" and DAS-38, "DTC Index".
Are any DTCs detected?
YES >> Perform the Diagnosis Procedure corresponding to the detected DTC.
NO >> GO TO 2.
2.CHECK OVERALL FUNCTION-I
WITH CONSULT-III
1. Turn ignition switch ON.
2. Select “BRAKE SW1” in “DAT A MONITOR” mode with CONSULT-III.
3. Check “BRAKE SW1” indication under the following conditions.
WITHOUT CONSULT-III
1. Turn ignition switch ON.
2. Check the voltage between ECM harness connector terminals under the following conditions.
Is the inspection result normal?
YES >> GO TO 8.
NO >> GO TO 3.
3.CHECK ICC BRAKE SWITCH POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Disconnect ICC brake switch harness connector.
3. Turn ignition switch ON.
4. Check the voltage between ICC brake switch harness connector and ground.
Vehicle speed More than 30 km/h (19 mph)
Selector lever Suitable position
Driving location Depress the brake pedal for more than 5 seconds so as
not to come off from the above-mentioned vehicle speed.
Monitor item Condition Indication
BRAKE SW1
(ICC brake switch) Brake pedalSlightly depressed OFF
Fully released ON
ECM Condition Voltage (V)
Connector +–
Te r m i n a l Te r m i n a l
E80 147
(ICC brake switch signal) 175 Brake pedalSlightly depressed Approx. 0
Fully released Battery voltage
ICC brake switch
Ground Voltage
Connector Terminal
E68 1 Ground Battery voltage
Revision: 2010 May2011 QX56

EC-448
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P1574 ASCD VEHICL
E SPEED SENSOR
YES >> GO TO 2.
NO >> Perform Diagnosis Procedure corresponding to the DTC indicated.
2.CHECK DTC WITH “ABS ACTUATOR A ND ELECTRIC UNIT (CONTROL UNIT)”
Refer to BRC-40, "
CONSULT-III Function".
Is the inspection result normal?
YES >> GO TO 3.
NO >> Perform Diagnosis Procedure corresponding to the DTC indicated.
3.CHECK DTC WITH “COMBINATION METER”
Refer to MWI-30, "
CONSULT-III Function".
>> INSPECTION END
Revision: 2010 May2011 QX56

EC-450
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P1574 ICC VEHICLE SPEED SENSOR
NO >> Perform Diagnosis Procedure corresponding to the DTC indicated.
2.CHECK DTC WITH “ABS ACTUATOR A
ND ELECTRIC UNIT (CONTROL UNIT)”
Refer to BRC-40, "
CONSULT-III Function".
Is the inspection result normal?
YES >> GO TO 3.
NO >> Perform Diagnosis Procedure corresponding to the DTC indicated.
3.CHECK DTC WITH “COMBINATION METER”
Check combination meter function.
Refer to MWI-30, "
CONSULT-III Function".
>> INSPECTION END
Revision: 2010 May2011 QX56

EC-460
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P2101 ELECTRIC THROTTLE CONTROL FUNCTION
P2101 ELECTRIC THROTTL
E CONTROL FUNCTION
DescriptionINFOID:0000000006217962
Electric throttle control actuator consists of th rottle control motor, throttle position sensor, etc.
The throttle control motor is operated by the ECM and it opens and closes the throttle valve.
The current opening angle of the throttle valve is detected by the throttle position sensor and it provides feed-
back to the ECM. ECM controls the throttle valve openi ng angle in response to driving condition via the throttle
control motor.
DTC LogicINFOID:0000000006217963
DTC DETECTION LOGIC
NOTE:
 If DTC P2101 is displayed with DTC P2100, first pe rform the trouble diagnosis for DTC P2100. Refer
to EC-458, "
DTC Logic".
 If DTC P2101 is displayed with DTC P2119, first pe rform the trouble diagnosis for DTC P2119. Refer
to EC-466, "
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. Turn ignition switch ON and wait at least 2 seconds.
2. Start engine and let it idle for 5 seconds.
3. Check DTC.
Is DTC detected?
YES >> Go to EC-460, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217964
1.CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT-I
1. Check the voltage between ECM harness connector and ground under the following conditions.
Is the inspection result normal?
YES >> GO TO 8.
NO >> GO TO 2.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P2101 Electric throttle control
performance Electric throttle control function does not
operate properly.  Harness or connectors
(Throttle control motor circuit is open or shorted)
 Electric throttle control actuator
ECM Ground Condition Voltage
Connector Terminal
E80 173 Ground Ignition switch:
OFF
Approx. 0 V
Ignition switch:
ON Battery voltage
Revision: 2010 May2011 QX56