ESP INFINITI QX56 2008 Factory Owner's Guide

P0031, P0032, P0051, P0052 A/F SENSOR 1 HEATER
EC-97
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P0031, P0032, P0051, P0052
A/F SENSOR 1 HEATER
DescriptionINFOID:0000000001351384
SYSTEM DESCRIPTION
The ECM performs ON/OFF duty control of the A/F sensor 1 heater corresponding to the engine operating
condition to keep the temperature of A/F sensor 1 element at the specified range.
On Board Diagnosis LogicINFOID:0000000001351378
DTC Confirmation ProcedureINFOID:0000000001351379
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confi rm that battery voltage is between 10.5V and 16V at
idle.
WITH CONSULT-III
1. Start engine and let it idle for at least 10 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-97, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351381
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Sensor Input Signal to ECM ECM functionActuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS) Engine speed
Air fuel ratio (A/F) sensor 1
heater controlAir fuel ratio (A/F) sensor 1
heater
Mass air flow sensor Amount of intake air
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0031
0031
(Bank 1) Air fuel ratio (A/F) sensor
1 heater control circuit low The current amperage in the air fuel ratio (A/F) sen-
sor 1 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the air fuel ratio (A/F) sensor 1 heater.) • Harness or connectors
(The A/F sensor 1 heater circuit is
open or shorted.)
• A/F sensor 1 heater
P0051
0051
(Bank 2)
P0032
0032
(Bank 1)
Air fuel ratio (A/F) sensor
1 heater control circuit
high The current amperage in the air fuel ratio (A/F) sen-
sor 1 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the air fuel ratio (A/F) sensor 1 heater.) • Harness or connectors
(The A/F sensor 1 heater circuit is
shorted.)
• A/F sensor 1 heater
P0052
0052
(Bank 2)
Revision: March 2010
2008 QX56

EC-100
< COMPONENT DIAGNOSIS >[VK56DE]
P0037, P0038, P0057,
P0058 HO2S2 HEATER
P0037, P0038, P0057, P0058 HO2S2 HEATER
DescriptionINFOID:0000000001351385
SYSTEM DESCRIPTION
The ECM performs ON/OFF control of the heated oxy gen sensor 2 heater corresponding to the engine speed,
amount of intake air and engine coolant temperature.
OPERATION
On Board Diagn osis LogicINFOID:0000000001351387
DTC Confirmation ProcedureINFOID:0000000001351388
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following pr ocedure, confirm that battery voltage is between 10.5V and 16V at
idle.
WITH CONSULT-III
1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.
2. Start engine and warm it up to the normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start the engine and keep the engine speed between 3,500 rpm and 4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 1 minute.
6. Check 1st trip DTC.
Sensor Input signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS) Engine speed
Heated oxygen sensor 2
heater controlHeated oxygen sensor 2 heater
Engine coolant temperature sensor Engine coolant temperature
Mass air flow sensor Amount of intake air
Engine speed rpm Heated oxygen sensor 2 heater
Above 3,600 OFF
Below 3,600 rpm after the following conditions are met.
• Engine: After warming up
• Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and at idle for 1 minute under no load ON
DTC No. Trouble diagnosis name
DTC detecting conditionPossible cause
P0037
0037
(Bank 1) Heated oxygen sensor 2
heater control circuit low The current amperage in the heated oxygen sen-
sor 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
P0057
0057
(Bank 2)
P0038
0038
(Bank 1)
Heated oxygen sensor 2
heater control circuit high The current amperage in the heated oxygen sen-
sor 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
P0058
0058
(Bank 2)
Revision: March 2010
2008 QX56

P0101 MAF SENSOREC-107
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Procedure for Malfunction B-a
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature. If engine cannot be started, go to EC-109, "
Diagnosis Procedure".
2. Select “DATA MONITOR” mode with CONSULT-III.
3. Check the voltage of “MAS A/F SE-B1” with “DATA MONITOR”.
4. Increases engine speed to about 4,000 rpm.
5. Monitor the linear voltage rise in response to engine speed
increases.
If NG, go to EC-109, "
Diagnosis Procedure".
If OK, go to following step.
6. Maintain the following conditions for at least 10 consecutive seconds. CAUTION:
Always drive vehicle at a safe speed.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to EC-109, "
Diagnosis Procedure".
Procedure for Malfunction B-b
WITH CONSULT-III
1. Start engine and warm it up to normal operating temperature.
Vehicle specification Vehicle serial number Procedure
2WD with ASCD Up to 912536
B-a
From 912537 B-b
2WD with ICC Up to 914347
B-a
From 914348 B-b
4WD with ASCD Up to 913067
B-a
From 913068 B-b
4WD with ICC Up to 912422
B-a
From 912423 B-b
PBIB3457E
ENG SPEEDMore than 2,000 rpm
TP SEN 1-B1 More than 3 V
TP SEN 2-B1 More than 3 V
Selector lever Suitable position
Driving location Driving vehicle uphill (Increased engine load) will help
maintain the driving conditions required for this test.
Revision: March 2010
2008 QX56

EC-108
< COMPONENT DIAGNOSIS >[VK56DE]
P0101 MAF SENSOR
If engine cannot be started, go to
EC-109, "Diagnosis Procedure".
2. Select “DATA MONITOR” mode with CONSULT-III.
3. Check the voltage of “MAS A/F SE-B1” with “DATA MONITOR”.
4. Increases engine speed to about 4,000 rpm.
5. Monitor the linear voltage rise in response to engine speed increases.
If NG, go to EC-109, "
Diagnosis Procedure".
If OK, go to following step.
6. Maintain the following conditions for at least 10 consecutive seconds. CAUTION:
Always drive vehicle at a safe speed.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to EC-109, "
Diagnosis Procedure".
Overall Function CheckINFOID:0000000001351405
PROCEDURE FOR MALFUNCTION B
Use this procedure to check the overall function of the mass air flow sensor circuit. During this check, a 1st trip
DTC might not be confirmed.
With GST
1. Start engine and warm it up to normal operating temperature.
2. Select Service $01 with GST.
3. Check the mass air flow sensor signal with Service $01.
4. Check for linear mass air flow sensor signal value rise in response to increases to about 4,000 rpm in engine speed.
5. If NG, go to EC-109, "
Diagnosis Procedure".
PBIB3457E
ENG SPEED More than 2,000 rpm
TP SEN 1-B1 More than 1.5 V
TP SEN 2-B1 More than 1.5 V
Selector lever Suitable position
Driving location Driving vehicle uphill (Increased engine load) will help
maintain the driving conditions required for this test.
SEF534P
Revision: March 2010
2008 QX56

P0101 MAF SENSOREC-111
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OK >> GO TO 11.
NG >> Replace mass air flow sensor.
11 .CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
>> INSPECTION END
Component InspectionINFOID:0000000001351408
MASS AIR FLOW SENSOR
With CONSULT-III
1. Reconnect all harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Connect CONSULT-III and select “DATA MONITOR” mode.
4. Select “MAS A/F SE-B1” and check i ndication under the following conditions.
*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm.
5. If the voltage is out of specification, proceed the following.
a. Check for the cause of uneven air flow through mass air flow sensor. Refer to following. • Crushed air ducts
• Malfunctioning seal of air cleaner element
• Uneven dirt of air cleaner element
• Improper specification of intake air system parts
b. If NG, repair or replace malfunctioning part and perform step 2 to 4 again. If OK, go to next step.
6. Turn ignition switch OFF.
7. Disconnect mass air flow sensor har ness connector and reconnect it again.
8. Perform step 2 to 4 again.
9. If NG, clean or replace mass air flow sensor.
Without CONSULT-III
1. Reconnect all harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Check voltage between ECM terminal 51 (Mass air flow sensor signal) and ground.
*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm.
Condition MAS A/F SE-B1 (V)
Ignition switch ON (Engine stopped.) Approx. 0.4
Idle (Engine is warmed-up to normal
operating temperature.) 1.0 - 1.3
2,500 rpm (Engine is warmed-up to
normal operating temperature.) 1.7 - 2.1
Idle to about 4,000 rpm 1.0 - 1.3 to Approx. 2.4*
ConditionMAS A/F SE-B1 (V)
Ignition switch ON (Engine stopped.) Approx. 0.4
Idle (Engine is warmed-up to normal
operating temperature.) 1.0 - 1.3
2,500 rpm (Engine is warmed-up to
normal operating temperature.) 1.7 - 2.1
Idle to about 4,000 rpm 1.0 - 1.3 to Approx. 2.4*
PBIB1106E
Revision: March 2010 2008 QX56

EC-116
< COMPONENT DIAGNOSIS >[VK56DE]
P0102, P0103 MAF SENSOR
With CONSULT-III
1. Reconnect all harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Connect CONSULT-III and select “DATA MONITOR” mode.
4. Select “MAS A/F SE-B1” and check i
ndication under the following conditions.
*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm.
5. If the voltage is out of specification, proceed the following.
a. Check for the cause of uneven air flow through mass air flow sensor. Refer to following. • Crushed air ducts
• Malfunctioning seal of air cleaner element
• Uneven dirt of air cleaner element
• Improper specification of intake air system parts
b. If NG, repair or replace malfunc tioning part and perform step 2 to 4 again.
If OK, go to next step.
6. Turn ignition switch OFF.
7. Disconnect mass air flow sensor harness connector and reconnect it again.
8. Perform step 2 to 4 again.
9. If NG, clean or replace mass air flow sensor.
Without CONSULT-III
1. Reconnect all harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Check voltage between ECM terminal 51 (Mass air flow sensor signal) and ground.
*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm.
4. If the voltage is out of spec ification, proceed the following.
a. Check for the cause of uneven air flow through mass air flow sensor. Refer to following. • Crushed air ducts
• Malfunctioning seal of air cleaner element
• Uneven dirt of air cleaner element
• Improper specification of intake air system parts
b. If NG, repair or replace malfunc tioning part and perform step 2 and 3 again.
If OK, go to next step.
5. Turn ignition switch OFF.
6. Disconnect mass air flow sensor harness connector and reconnect it again.
7. Perform step 2 and 3 again.
Condition MAS A/F SE-B1 (V)
Ignition switch ON (Engine stopped.) Approx. 0.4
Idle (Engine is warmed-up to normal
operating temperature.) 1.0 - 1.3
2,500 rpm (Engine is warmed-up to
normal operating temperature.) 1.7 - 2.1
Idle to about 4,000 rpm 1.0 - 1.3 to Approx. 2.4*
ConditionMAS A/F SE-B1 (V)
Ignition switch ON (Engine stopped.) Approx. 0.4
Idle (Engine is warmed-up to normal
operating temperature.) 1.0 - 1.3
2,500 rpm (Engine is warmed-up to
normal operating temperature.) 1.7 - 2.1
Idle to about 4,000 rpm 1.0 - 1.3 to Approx. 2.4*
PBIB1106E
Revision: March 2010 2008 QX56

EC-118
< COMPONENT DIAGNOSIS >[VK56DE]
P0112, P0113 IAT SENSOR
P0112, P0113 IAT SENSOR
Component DescriptionINFOID:0000000001351418
The intake air temperature sensor is built-into mass air flow sensor.
The sensor detects intake air temperature and transmits a signal to
the ECM.
The temperature sensing unit uses a
thermistor which is sensitive to
the change in temperature. Electrical resistance of the thermistor
decreases in response to the temperature rise.

*: This data is reference value and is measured between ECM terminal 34 (Intake air
temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output
voltage. Doing so may result in damage to the ECM's transistor.
Use a ground other than ECM terminals, such as the ground.
On Board Diagnosis LogicINFOID:0000000001351419
DTC Confirmation ProcedureINFOID:0000000001351420
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-III
1. Turn ignition switch ON.
2. Wait at least 5 seconds.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to EC-118, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351422
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
BBIA0355E
Intake air temperature °C ( °F) Voltage* V
Resistance kΩ
25 (77) 3.31.800 - 2.200
80 (176) 1.20.283 - 0.359
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0112
0112 Intake air temperature
sensor circuit low input An excessively low voltage from the sensor is
sent to ECM.
• Harness or connectors
(The sensor circuit is open or shorted.)
• Intake air temperature sensor
P0113
0113 Intake air temperature
sensor circuit high input An excessively high voltage from the sensor is
sent to ECM.
Revision: March 2010
2008 QX56

EC-128
< COMPONENT DIAGNOSIS >[VK56DE]
P0122, P0123 TP SENSOR
P0122, P0123 TP SENSOR
Component DescriptionINFOID:0000000001351432
Electric throttle control actuator consists of throttle control motor,
throttle position sensor, etc. The throttle position sensor responds to
the throttle valve movement.
The throttle position sensor has the two sensors. These sensors are
a kind of potentiometers which transform the throttle valve position
into output voltage, and emit the voltage signal to the ECM. In addi-
tion, these sensors detect the opening and closing speed of the
throttle valve and feed the voltage signals to the ECM. The ECM
judges the current opening angle of the
throttle valve from these sig-
nals and the ECM controls the throttle control motor to make the
throttle valve opening angle properly in response to driving condi-
tion.
On Board Diagn osis LogicINFOID:0000000001351434
These self-diagnoses have the one trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000001351435
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 8V at idle.
WITH CONSULT-III
1. Start engine and let it idle for 1 second.
2. Check DTC.
3. If DTC is detected, go to EC-128, "
Diagnosis Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351437
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
PBIB0145E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0122
0122 Throttle position sensor
2 circuit low input An excessively low voltage from the TP sensor
2 is sent to ECM. • Harness or connectors
(TP sensor 2 circuit is open or shorted.)
(APP sensor 2 circuit is shorted.)
• Electric throttle control actuator
(TP sensor 2)
• Accelerator pedal position sensor (APP sensor 2)
P0123
0123
Throttle position sensor
2 circuit high input An excessively high voltage from the TP sensor
2 is sent to ECM.
Engine operation condition in fail-safe mode
The ECM controls the electric throttle control actuator in regulating the throttle opening in order for the idle position to be within +10
degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal condition.
So, the acceleration will be poor.
Revision: March 2010 2008 QX56

P0127 IAT SENSOREC-135
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P0127 IAT SENSOR
Component DescriptionINFOID:0000000001351446
The intake air temperature sensor is
built into mass air flow sensor.
The sensor detects intake air temperature and transmits a signal to
the ECM.
The temperature sensing unit uses a thermistor which is sensitive to
the change in temperature. Electrical resistance of the thermistor
decreases in response to the temperature rise.

*: This data is reference value and is measured between ECM terminal 34 (Intake air
temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output
voltage. Doing so may result in damage to the ECM's transistor.
Use a ground other than ECM te rminals, such as the ground.
On Board Diagnosis LogicINFOID:0000000001351447
DTC Confirmation ProcedureINFOID:0000000001351448
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
CAUTION:
Always drive vehicle at a safe speed.
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.
WITH CONSULT-III
1. Wait until engine coolant temperature is less than 90 °C (194 °F)
a. Turn ignition switch ON.
b. Select “DATA MONITOR” mode with CONSULT-III.
c. Check the engine coolant temperature.
d. If the engine coolant temperature is not less than 90 °C (194° F), turn ignition switch OFF and cool down
engine.
• Perform the following steps before engine coolant temperature is above 90 °C (194° F).
2. Turn ignition switch ON.
BBIA0355E
Intake air temperature °C ( °F) Voltage* V
Resistance kΩ
25 (77) 3.31.800 - 2.200
80 (176) 1.20.283 - 0.359
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0127
0127 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 sensor circuit is open or shorted)
• Intake air temperature sensor
Revision: March 2010 2008 QX56

P0133, P0153 A/F SENSOR 1EC-153
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P0133, P0153 A/F SENSOR 1
Component DescriptionINFOID:0000000001351479
The air fuel ratio (A/F) sensor 1 is a planar one-cell limit current sen-
sor. The sensor element of the A/F sensor 1 is composed an elec-
trode layer, which transports ions. It has a heater in the element.
The sensor is capable of precise m
easurement = 1, but also in the
lean and rich range. Together with its control electronics, the sensor
outputs a clear, continuous signal throughout a wide range.
The exhaust gas components diffuse through the diffusion layer at
the sensor cell. An electrode layer is applied voltage, and this current
relative oxygen density in lean. Also this current relative hydrocar-
bon density in rich.
Therefore, the A/F sensor 1 is able to indicate air fuel ratio by this
electrode layer of current. In addition, a heater is integrated in the
sensor to ensure the required operating temperature of about 800 °C
(1,472 °F).
On Board Diagnosis LogicINFOID:0000000001351481
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 tem perature index. Judgment is based on whether the com-
pensated time (the A/F signal cycling time index) is inordinately long or not.
DTC Confirmation ProcedureINFOID:0000000001351482
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
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. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1minute under no load.
PBIB3353E
PBIB3354E
DTC No. Trouble diagnosis nameDTC detecting conditionPossible Cause
P0133
0133
(Bank 1)
Air fuel ratio (A/F) sensor 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
0153
(Bank 2)
Revision: March 2010
2008 QX56