2011 INFINITI QX56 heater

P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
EC-181
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
DTC LogicINFOID:0000000006217775
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 10 seconds.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-181, "Diagnosis Procedure".
NG >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217776
1.CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect air fuel ratio (A /F) sensor 1 harness connector.
2. Turn ignition switch ON.
3. Check the voltage between A/F sensor 1 harness connector and ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
DTC No. Trouble diagnosis
(Trouble diagnosis content) DTC detecting condition Possible cause
P0031 A/F SEN1 HTR (B1)
[A/F sensor 1 heater (bank
1) control circuit low] The current amperage in the A/F sensor 1 heater
circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the A/F sensor 1 heater.)  Harness or connectors
(The A/F sensor 1 heater circuit is
open or shorted.)
 A/F sensor 1 heater
P0032 A/F SEN1 HTR (B1)
[A/F sensor 1 heater (bank
1) control circuit high] The current amperage in the A/F sensor 1 heater
circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the A/F sensor 1 heater.)  Harness or connectors
(The A/F sensor 1 heater circuit is
shorted.)
 A/F sensor 1 heater
P0051 A/F SEN1 HTR (B2)
[A/F sensor 1 heater (bank
2) control circuit low] The current amperage in the A/F sensor 1 heater
circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the A/F sensor 1 heater.)  Harness or connectors
(The A/F sensor 1 heater circuit is
open or shorted.)
 A/F sensor 1 heater
P0052 A/F SEN1 HTR (B2)
[A/F sensor 1 heater (bank
2) control circuit high] The current amperage in the A/F sensor 1 heater
circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the A/F sensor 1 heater.)  Harness or connectors
(The A/F sensor 1 heater circuit is
shorted.)
 A/F sensor 1 heater
DTC A/F sensor 1
Ground Voltage
Bank Connector Terminal
P0031, P0032 1 F67 5 Ground Battery voltage
P0051, P0052 2 F68 5
Revision: 2010 May2011 QX56

EC-182
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0031, P0032, P0051, P00
52 A/F SENSOR 1 HEATER
2.DETECT MALFUNCTIONING PART
Check the following.
 20 A fuse (No. 43)
 Harness for open or short between A/F sensor 1 and fuse
 Loose or poor connection for each connector and harness
>> Repair or replace harness or connectors.
3.CHECK A/F SENSOR 1 HEATER OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between A/F sensor 1 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 4.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
4.CHECK A/F SENSOR 1 HEATER
Refer to EC-182, "
Component Inspection (A/F Sensor 1 Heater)".
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 5.
5.REPLACE A/F SENSOR 1
Replace malfunctioning A/F sensor 1. Refer to EM-40, "
Exploded View".
CAUTION:
 Discard any A/F sensor which has b een dropped from a height of more than 0.5 m (19.7 in) onto a
hard surface such as a concrete floor; use a new one.
 Before installing new A/F sensor, clean exhau st system threads using Oxygen Sensor Thread
Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant
(commercial service tool).
>> INSPECTION END
6.CHECK INTERMITTENT INCIDENT
Perform GI-40, "
Intermittent Incident".
>> INSPECTION END
Component Inspection (A/F Sensor 1 Heater)INFOID:0000000006217777
1.CHECK AIR FUEL RATIO (A/F) SENSOR 1
1. Turn ignition switch OFF.
2. Disconnect air fuel ratio (A/F) sensor 1 harness connector.
3. Check resistance between A/F sensor 1 terminals as per the following.
DTC A/F sensor 1 ECM
Continuity
Bank Connector Terminal Connector Terminal
P0031, P0032 1 F67 2 F11048
Existed
P0051, P0052 2 F68 2 53
Terminal Resistance
2 and 5 2.0 - 3.2 Ω [at 25 °C (77 °F)]
Revision: 2010 May2011 QX56

P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
EC-183
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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OIs the inspection result normal?
YES >> INSPECTION END
NO >> GO TO 2.
2.REPLACE A/F SENSOR 1
Replace malfunctioning A/F sensor 1. Refer to EM-40, "
Exploded View".
CAUTION:
 Discard any A/F sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a
hard surface such as a concrete floor; use a new one.
 Before installing new A/F senso r, clean exhaust system threads using Oxygen Sensor Thread
Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant
(commercial service tool).
>> INSPECTION END
2 and 3, 4, 6 ∞ Ω
(Continuity should not exist)
5 and 3, 4, 6 Terminal Resistance
Revision: 2010 May2011 QX56

EC-184
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0037, P0038, P0057,
P0058 HO2S2 HEATER
P0037, P0038, P0057, P0058 HO2S2 HEATER
DTC LogicINFOID:0000000006217778
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. 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. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Go to EC-184, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217779
1.CHECK HEATED OXYGEN SENSOR 2 (HO2S2) POWER SUPPLY CIRCUIT
1. Disconnect heated oxygen sensor 2 (HO2S2) harness connector.
2. Turn ignition switch ON.
3. Check the voltage between HO2S2 harness connector and ground.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P0037 HO2S2 HTR (B1)
[Heated oxygen sensor 2
heater (bank 1) control cir-
cuit low] The current amperage in the heated oxygen sensor
2 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.)  Harness or connectors
(The heated oxygen sensor 2 heater
circuit is open or shorted.)
 Heated oxygen sensor 2 heater
P0038 HO2S2 HTR (B1)
[Heated oxygen sensor 2
heater (bank 1) control cir-
cuit high] The current amperage in the heated oxygen sensor
2 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.)  Harness or connectors
(The heated oxygen sensor 2 heater
circuit is shorted.)
 Heated oxygen sensor 2 heater
P0057 HO2S2 HTR (B2)
[Heated oxygen sensor 2
heater (bank 2) control cir-
cuit low] The current amperage in the heated oxygen sensor
2 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.)  Harness or connectors
(The heated oxygen sensor 2 heater
circuit is open or shorted.)
 Heated oxygen sensor 2 heater
P0058 HO2S2 HTR (B2)
[Heated oxygen sensor 2
heater (bank 2) control cir-
cuit high] The current amperage in the heated oxygen sensor
2 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.)  Harness or connectors
(The heated oxygen sensor 2 heater
circuit is shorted.)
 Heated oxygen sensor 2 heater
Revision: 2010 May2011 QX56

P0037, P0038, P0057, P0058 HO2S2 HEATER
EC-185
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
 20 A fuse (No. 43)
 Harness for open or short between heated oxygen sensor 2 and fuse
 Loose or poor connection for each connector and harness
>> Repair open circuit, short to ground or short to power in harness or connectors.
3.CHECK HO2S2 OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between HO2S2 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 4.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
4.CHECK HO2S2 HEATER
Refer to EC-186, "
Component Inspection (HO2 Sensor 2 Heater)".
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 5.
5.REPLACE HEATED OXYGEN SENSOR 2
Replace malfunctioning heated oxygen sensor 2. Refer to EX-5, "
Removal and Installation".
CAUTION:
 Discard any heated oxygen sensor which has been dr opped from a height of more than 0.5 m (19.7
in) onto a hard surface such as a concrete floor; use a new one.
 Before installing new oxygen sensor, clean exh aust system threads using Oxygen Sensor Thread
Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant
(commercial service tool).
>> INSPECTION END
6.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
DTC HO2S2
Ground Voltage
Bank Connector Terminal
P0037, P0038 1 F87 2 Ground Battery voltage
P0057, P0058 2 F88 2
DTC HO2S2 ECM
Continuity
Bank Connector Terminal Connector Terminal
P0037, P0038 1 F87 3 F 11147
Existed
P0057, P0058 2 F88 3 52
Revision: 2010 May2011 QX56

EC-186
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0037, P0038, P0057,
P0058 HO2S2 HEATER
Component Inspection (HO2 Sensor 2 Heater)
INFOID:0000000006217780
1.CHECK HEATED OXYGEN SENSOR 2 HEATER
1. Turn ignition switch OFF.
2. Disconnect heated oxygen sensor 2 (HO2S2) harness connector.
3. Check resistance between HO2S2 terminals as follows.
Is the inspection result normal?
YES >> INSPECTION END
NO >> GO TO 2.
2.REPLACE HEATED OXYGEN SENSOR 2
Replace malfunctioning heated oxygen sensor 2. Refer to EX-5, "
Removal and Installation".
CAUTION:
 Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7
in) onto a hard surface such as a concrete floor; use a new one.
 Before installing new oxygen sensor, clean exh aust system threads using Oxygen Sensor Thread
Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant
(commercial service tool).
>> INSPECTION END
Terminal Resistance2 and 3 3.4 - 4.4 Ω [at 25 °C (77 °F)]
1 and 2, 3, 4 ∞ Ω
(Continuity should not exist)
4 and 1, 2, 3
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-241
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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5. Also check harness for short to power.
Is the inspection result normal?
YES >> GO TO 7.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
7.CHECK A/F SENSOR 1 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
4. Also check harness for short to power.
Is the inspection result normal?
YES >> GO TO 8.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
8.CHECK A/F SENSOR 1 HEATER
Refer to EC-182, "
Component Inspection (A/F Sensor 1 Heater)".
Is the inspection result normal?
YES >> GO TO 9.
NO >> GO TO 12.
9.CHECK MASS AIR FLOW SENSOR
Check mass air flow sensor.
Refer to EC-190, "
Component Inspection (MAF Sensor)".
Is the inspection result normal?
YES >> GO TO 10.
NO >> Replace malfunctioning mass air flow sensor. Refer to EM-30, "
Removal and Installation".
10.CHECK PCV VALVE
Refer to EC-534, "
Inspection".
Is the inspection result normal?
YES >> GO TO 11.
NO >> Repair or replace PCV valve.
11 .CHECK INTERMITTENT INCIDENT
Perform GI-40, "
Intermittent Incident".
Is the inspection result normal?
YES >> GO TO 12.
NO >> Repair or replace malfunctioning part.
12.REPLACE A/F SENSOR 1
Replace malfunctioning A/F sensor 1. Refer to EM-40, "
Exploded View".
CAUTION:
 Discard any A/F sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a
hard surface such as a concrete floor; use a new one.
DTC A/F sensor 1 ECM
Ground Continuity
Bank Connector Terminal Connector Terminal
P0133 1 F67 3 F11088
Ground Not existed
P0153 2 F68 3 78
DTC A/F sensor 1 ECM
Continuity
Bank Connector Terminal Connector Terminal
P0133 1 F67 6 F 11194
Existed
P0153 2 F68 6 74
Revision: 2010 May2011 QX56