light INFINITI QX56 2008 Factory Manual Online

P0102, P0103 MAF SENSOREC-113
< COMPONENT DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
P0102, P0103 MAF SENSOR
Component DescriptionINFOID:0000000001351410
The mass air flow sensor is placed in
the stream of intake air. It mea-
sures the intake flow rate by measuring a part of the entire intake
flow. The mass air flow sensor c ontrols the temperature of the hot
wire to a certain amount. The heat generated by the hot wire is
reduced as the intake air flows around it. The more air, the greater
the heat loss.
Therefore, the electric current s upplied to the hot wire is changed to
maintain the temperature of the hot wire as air flow increases. The
ECM detects the air flow by means of this current change.
On Board Diagnosis LogicINFOID:0000000001351412
These self-diagnoses have the on e trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000001351413
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.
PROCEDURE FOR DTC P0102
With CONSULT-III
1. Start engine and wait at least 5 seconds.
2. Check DTC.
3. If DTC is detected, go to EC-114, "
Diagnosis Procedure".
With GST
Follow the procedure “With CONSULT-III” above.
PROCEDURE FOR DTC P0103
With CONSULT-III
1. Turn ignition switch ON.
2. Wait at least 5 seconds.
3. Check DTC.
4. If DTC is detected, go to EC-114, "
Diagnosis Procedure".
If DTC is not detected, go to next step.
5. Start engine and wait at least 5 seconds.
6. Check DTC.
7. If DTC is detected, go to EC-114, "
Diagnosis Procedure".
BBIA0355E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0102
0102 Mass air flow 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 leaks
• Mass air flow sensor
P0103
0103 Mass air flow sensor circuit
high input An excessively high voltage from the sensor is
sent to ECM. • Harness or connectors
(The sensor circuit is open or shorted.)
• Mass air flow sensor
Detected items Engine operating condition in fail-safe mode
Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
Revision: March 2010 2008 QX56

EC-124
< COMPONENT DIAGNOSIS >[VK56DE]
P0117, P0118 ECT SENSOR
P0117, P0118 ECT SENSOR
Component DescriptionINFOID:0000000001351425
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor modifies a voltage signal from the
ECM. The modified signal returns to the ECM as the engine coolant
temperature input. The sensor uses
a thermistor which is sensitive to
the change in temperature. The elec trical resistance of the ther-
mistor decreases as temperature increases.

*: This data is reference value and is measured between ECM terminal 73 (Engine
coolant temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doi ng so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
On Board Diagnosis LogicINFOID:0000000001351426
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, the ECM enters fail-safe mode and the MIL lights up.
SEF594K
Engine coolant temperature
°C ( °F) Voltage* V
Resistance kΩ
–10 (14) 4.47.0 - 11.4
20 (68) 3.52.1 - 2.9
50 (122) 2.20.68 - 1.00
90 (194) 0.90.236 - 0.260
SEF012P
DTC
No. Trouble Diagnosis Na
meDTC Detecting Cond ition Possible Cause
P0117
0117 Engine coolant 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.)
• Engine coolant temperature sensor
P0118
0118 Engine coolant temperature
sensor circuit high input An excessively high voltage from the sensor is
sent to ECM.
Detected items
Engine operating condition in fail-safe mode
Engine coolant temper- ature sensor circuit Engine coolant temperature will be determined by ECM based on the following condition.
CONSULT-III displays the engine coolant temperature decided by ECM.
Condition Engine coolant temperature decided
(CONSULT-III display)
Just as ignition switch is turned ON or START 40°C (104 °F)
Approx 4 minutes or more after engine starting 80°C (176 °F)
Except as shown above 40 - 80
°C (104 - 176 °F)
(Depends on the time)
When the fail-safe system for engine coolant temperature sensor is activated, the cooling fan operates while
engine is running.
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

EC-176
< COMPONENT DIAGNOSIS >[VK56DE]
P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
On Board Diagn
osis LogicINFOID:0000000001351513
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio f eedback signal from the A/F sensors 1. The ECM calcu-
lates the necessary compensation to correct the of fset between the actual and the theoretical ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC Confirmation ProcedureINFOID:0000000001351514
NOTE:
Check vehicle specifications and VIN, then select the procedure to be performed. (Refer to the table below.)
PROCEDURE A
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. 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 and select “SELF-LE ARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-III.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Start engine again and let it idle for at least 10 minutes.
6. Check 1st trip DTC. The 1st trip DTC P0171 or P0174 should be detected at this stage, if a malfunction exists. If so, go to EC-
179, "Diagnosis Procedure".
NOTE:
If 1st trip DTC is not detected during above proc edure, performing the following procedure is advised.
SensorInput signal to ECM ECM functionActuator
A/F sensor 1 Density of oxygen in exhaust gas
(Mixture ratio feedback signal)
Fuel injection control Fuel injector
DTC No. Trouble diagnosis name
DTC detecting conditionPossible cause
P0171
0171
(Bank 1) Fuel injection system too
lean • Fuel injection system does not operate properly.
• The amount of mixture ratio compensation is too
large. (The mixture ratio is too lean.) • Intake air leaks
• A/F sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Mass air flow sensor
• Incorrect PCV hose connection
P0174
0174
(Bank 2)
Vehicle specification Vehicle serial number
Procedure
2WD with ASCD Up to 912536
A
From 912537 B
2WD with ICC Up to 914347
A
From 914348 B
4WD with ASCD Up to 913067
A
From 913068 B
4WD with ICC Up to 912422
A
From 912423 B
Revision: March 2010 2008 QX56

EC-182
< COMPONENT DIAGNOSIS >[VK56DE]
P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
On Board Diagn
osis LogicINFOID:0000000001351517
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio f eedback signal from the A/F sensors 1. The ECM calcu-
lates the necessary compensation to correct the of fset between the actual and the theoretical ratios.
In case the amount of the compensation value is extrem ely large (The actual mixture ratio is too rich.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC Confirmation ProcedureINFOID:0000000001351518
NOTE:
Check vehicle specifications and VIN, then select the procedure to be performed. (Refer to the table below.)
PROCEDURE A
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. 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 and select “SELF-LE ARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-III.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Start engine again and let it idle for at least 10 minutes.
6. Check 1st trip DTC. The 1st trip DTC P0172, P0175 should be detected at th is stage, if a malfunction exists. If so, go to EC-
185, "Diagnosis Procedure".
NOTE:
If 1st trip DTC is not detected during above proc edure, performing the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
Sensor Input signal to ECM ECM functionActuator
A/F sensor 1 Density of oxygen in exhaust gas
(Mixture ratio
feedback signal) Fuel injection control Fuel injector
DTC No. Trouble diagnosis name
DTC detecting conditionPossible cause
P0172
0172
(Bank 1) Fuel injection system too
rich • Fuel injection system does not operate properly.
• The amount of mixture ratio compensation is too
large. (The mixture ratio is too rich.) • A/F sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Mass air flow sensor
P0175
0175
(Bank 2)
Vehicle specification Vehicle serial number
Procedure
2WD with ASCD Up to 912536
A
From 912537 B
2WD with ICC Up to 914347
A
From 914348 B
4WD with ASCD Up to 913067
A
From 913068 B
4WD with ICC Up to 912422
A
From 912423 B
Revision: March 2010 2008 QX56

EC-194
< COMPONENT DIAGNOSIS >[VK56DE]
P0222, P0223 APP SENSOR
P0222, P0223 APP SENSOR
Component DescriptionINFOID:0000000001351535
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:0000000001351537
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:0000000001351538
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-194, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351540
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
P0222
0222 Throttle position sensor
1 circuit low input An excessively low voltage from the TP sensor
1 is sent to ECM. • Harness or connectors
(TP sensor 1 circuit is open or shorted.)
(APP sensor 2 circuit is shorted.)
• Electric throttle control actuator
(TP sensor 1)
• Accelerator pedal position sensor (APP sensor 2)
P0223
0223
Throttle position sensor
1 circuit high input An excessively high voltage from the TP sensor
1 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

EC-198
< COMPONENT DIAGNOSIS >[VK56DE]
P0300, P0301, P0302, P
0303, P0304, P0305, P0306, P0307, P0308 MISFIRE
P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MIS-
FIRE
On Board Diagn osis LogicINFOID:0000000001351543
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crank-
shaft position (CKP) sensor (POS) signal to vary , ECM can determine that a misfire is occurring.
The misfire detection logic consists of the following two conditions.
1. One Trip Detection Logic (Three Way Catalyst Damage) On the 1st trip that a misfire condition occurs that can damage the three way catalyst (TWC) due to over-
heating, the MIL will blink.
When a misfire condition occurs, the ECM monitors the CKP sensor signal every 200 engine revolutions
for a change.
When the misfire condition decreases to a level that will not damage the TWC, the MIL will turn off.
If another misfire condition occurs that can dam age the TWC on a second trip, the MIL will blink.
When the misfire condition decreases to a level that will not damage the TWC, the MIL will remain on.
If another misfire condition occurs that can damage the TWC, the MIL will begin to blink again.
2. Two Trip Detection Logic (Exhaust quality deterioration) For misfire conditions that will not damage the TWC (but will affect vehicle emissions), the MIL will only
light when the misfire is detected on a second trip. Du ring this condition, the ECM monitors the CKP sen-
sor signal every 1,000 engine revolutions.
A misfire malfunction can be detected on any one cylinder or on multiple cylinders.
DTC Confirmation ProcedureINFOID:0000000001351544
CAUTION:
Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws when driv-
ing.
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
Sensor Input signal to ECM ECM function
Crankshaft position sensor (POS) Engine speedOn board diagnosis of misfire
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0300
0300 Multiple cylinder misfire
detected
Multiple cylinder misfire.
• Improper spark plug
• Insufficient compression
• Incorrect fuel pressure
• The injector circuit is open or shorted
• Fuel injector
• Intake air leak
• The ignition signal circuit is open or short-ed
• Lack of fuel
• Signal plate
• Air fuel ratio (A/F) sensor 1
• Incorrect PCV hose connection
P0301
0301
No.1 cylinder misfire de-
tected
No. 1 cylinder misfires.
P0302
0302 No. 2 cylinder misfire
detected
No. 2 cylinder misfires.
P0303
0303 No. 3 cylinder misfire
detected
No. 3 cylinder misfires.
P0304
0304 No. 4 cylinder misfire
detected
No. 4 cylinder misfires.
P0305
0305 No. 5 cylinder misfire
detected
No. 5 cylinder misfires.
P0306
0306 No. 6 cylinder misfire
detected
No. 6 cylinder misfires.
P0307
0307 No. 7 cylinder misfire
detected
No. 7 cylinder misfires.
P0308
0308 No. 8 cylinder misfire
detected
No. 8 cylinder misfires.
Revision: March 2010
2008 QX56

EC-204
< COMPONENT DIAGNOSIS >[VK56DE]
P0327, P0328,
P0332, P0333 KS
P0327, P0328, P0332, P0333 KS
Component DescriptionINFOID:0000000001351546
The knock sensor is attached to t he cylinder block. It senses engine
knocking using a piezoelectric element. A knocking vibration from
the cylinder block is sensed as vibrational pressure. This pressure is
converted into a voltage signal and sent to the ECM.
On Board Diagn osis LogicINFOID:0000000001351547
The MIL will not light up for these self-diagnoses.
DTC Confirmation ProcedureINFOID:0000000001351548
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 10V at idle.
WITH CONSULT-III
1. Start engine and run it for at least 5 seconds at idle speed.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-204, "
Diagnosis Procedure"
With GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351550
1.CHECK KNOCK SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-I
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check resistance between ECM terminals 15, 36 and ground. Refer to Wiring Diagram. NOTE:
It is necessary to use an ohmmeter which can measure more than 10 M Ω.
PBIB0021E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0327
0327
(bank 1) Knock sensor circuit low in-
put An excessively low voltage from the sensor
is sent to ECM.
• Harness or connectors(The sensor circuit is open or shorted.)
• Knock sensor
P0332
0332
(bank 2)
P0328
0328
(bank 1)
Knock sensor circuit high in-
put An excessively high voltage from the sensor
is sent to ECM.
P0333
0333
(bank 2)
Revision: March 2010 2008 QX56

P0441 EVAP CONTROL SYSTEMEC-221
< COMPONENT DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O

With CONSULT-III
1. Disconnect vacuum hose connected to EVAP canister purge volume control solenoid valve at EVAP ser-
vice port and install vacuum gauge. For the location of EVAP service port, refer to EC-37, "
Description".
2. Start engine and let it idle.
3. Select “PURG VOL CONT/V” in “ACTIVE TEST” mode with CONSULT-III.
4. Rev engine up to 2,000 rpm.
5. Touch “Qd” and “Qu” on CONSULT-III screen to adjust “PURG VOL CONT/V” opening and check vacuum
existence.
OK or NG
OK >> GO TO 7.
NG >> GO TO 4.
3.CHECK PURGE FLOW
Without CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Stop engine.
3. Disconnect vacuum hose connected to EVAP canister purge volume control solenoid valve at EVAP ser-
vice port and install vacuum gauge. For the location of EVAP service port, refer to EC-37, "
Description".
4. Start engine and let it idle.
Do not depress accelerator pedal even slightly.
5. Check vacuum gauge indication before 60 seconds passed after starting engine.
6. Revving engine up to 2,000 rpm after 100 seconds passed after starting engine.
OK or NG
OK >> GO TO 7.
NG >> GO TO 4.
4.CHECK EVAP PURGE LINE
1. Turn ignition switch OFF.
2. Check EVAP purge line for improper connection or disconnection. Refer to EC-37, "
Description".
OK or NG
OK >> GO TO 5.
NG >> Repair it.
5.CHECK EVAP PURGE HOSE AND PURGE PORT
1. Disconnect purge hoses connect ed to EVAP service port A and
EVAP canister purge volume control solenoid valve B.
2. Blow air into each hose and EVAP purge port C.
PURG VOL CONT/V Vacuum
100% Should exist.
0% Should not exist.
Vacuum should not exist.
Vacuum should exist.
SEF367U
Revision: March 2010 2008 QX56

P0451 EVAP CONTROL SYSTEM PRESSURE SENSOREC-247
< COMPONENT DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
P0451 EVAP CONTROL SYST
EM PRESSURE SENSOR
Component DescriptionINFOID:0000000001351610
The EVAP control system pressure sens or detects pressure in the purge line. The sensor output voltage to the
ECM increases as pressure increases.
On Board Diagnosis LogicINFOID:0000000001351612
NOTE:
If DTC P0451 is displayed with DTC P0643, first pe rform the trouble diagnosis for DTC P0643. Refer to
EC-293
.
DTC Confirmation ProcedureINFOID:0000000001351613
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. Start engine and wait at least 40 seconds. NOTE:
Do not depress accelerator pedal even slightly.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to EC-247, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351614
1.CHECK GROUND CONNECTIONS
BBIA0443E
PBIB1207E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0451
0451 EVAP control system pressure
sensor performance ECM detects a sloshing signal from the
EVAP control system pressure sensor • Harness or connectors
• EVAP control system pressure sensor
Revision: March 2010
2008 QX56