check engine light INFINITI QX56 2009 Factory Owner's Manual

P0102, P0103 MAF SENSOREC-109
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P0102, P0103 MAF SENSOR
Component DescriptionINFOID:0000000003771359
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:0000000003771360
These self-diagnoses have the on e trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003771361
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
PROCEDURE FOR DTC P0102
1. Start engine and wait at least 5 seconds.
2. Check DTC.
3. If DTC is detected, go to EC-110, "Diagnosis Procedure"
.
PROCEDURE FOR DTC P0103
1. Turn ignition switch ON.
2. Wait at least 5 seconds.
3. Check DTC.
4. If DTC is detected, go to EC-110, "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-110, "Diagnosis Procedure"
.
BBIA0355E
DTC No. Trouble diagnosis name DTC detecting condition Possible 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: December 20092009 QX56

EC-124
< COMPONENT DIAGNOSIS >[VK56DE]
P0122, P0123 TP SENSOR
P0122, P0123 TP SENSOR
Component DescriptionINFOID:0000000003771379
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 t he 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:0000000003771380
These self-diagnoses have the one trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003771381
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 8V at idle.
1. Start engine and let it idle for 1 second.
2. Check DTC.
3. If DTC is detected, go to EC-124, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771382
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: December 20092009 QX56

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-169
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P0171, P0174 FUEL INJE
CTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000003771433
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 lean.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC Confirmation ProcedureINFOID:0000000003771434
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
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-LEARNING 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-
170, "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.
b. Start engine and drive the vehicle under the similar condi tions to (1st trip) Freeze Frame Data for 10 min-
utes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Da ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
Sensor Input signal to ECM ECM function Actuator
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 condition Possible 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)
Engine speed Engine speed in the freeze frame data
± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Revision: December 20092009 QX56

EC-174
< COMPONENT DIAGNOSIS >[VK56DE]
P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
P0172, P0175 FUEL INJE
CTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000003771436
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:0000000003771437
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
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-
175, "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.
b. Start engine and drive the vehicle under the similar conditions to (1st trip) Freeze Frame Data for 10 min- utes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Da ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
Sensor Input signal to ECM ECM function Actuator
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 condition Possible 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)
Engine speed Engine speed in the freeze frame data
± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)
Revision: December 20092009 QX56

P0222, P0223 APP SENSOREC-185
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P0222, P0223 APP SENSOR
Component DescriptionINFOID:0000000003771449
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 t he 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 t he 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 Diagnosis LogicINFOID:0000000003771450
These self-diagnoses have the on e trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM ent ers fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003771451
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 8V at idle.
1. Start engine and let it idle for 1 second.
2. Check DTC.
3. If DTC is detected, go to EC-185, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771452
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: December 20092009 QX56

P0327, P0328, P0332, P0333 KS
EC-195
< COMPONENT DIAGNOSIS > [VK56DE]
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P0327, P0328, P0332, P0333 KS
Component DescriptionINFOID:0000000003771457
The knock sensor is attached to t
he cylinder block. It senses engine
knocking using a piezoelectric el ement. 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 Diagnosis LogicINFOID:0000000003771458
The MIL will not light up for these self-diagnoses.
DTC Confirmation ProcedureINFOID:0000000003771459
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10V at idle.
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-195, "Diagnosis Procedure"
Diagnosis ProcedureINFOID:0000000003771460
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 condition Possible 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)
Resistance: Approximately 532 - 588 k Ω [at 20 °C (68 °F)]
Revision: December 20092009 QX56

EC-212
< COMPONENT DIAGNOSIS >[VK56DE]
P0441 EVAP CONTROL SYSTEM
OK (Without CONSULT-III)>>GO TO 3.
NG >> Replace EVAP canister.
2.CHECK PURGE FLOW
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 “A CTIVE 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
PURG VOL CONT/V Vacuum
100% Should exist.0% Should not exist.
Vacuum should not exist.
Vacuum should exist.
Revision: December 20092009 QX56

EC-238
< COMPONENT DIAGNOSIS >[VK56DE]
P0451 EVAP CONTROL S
YSTEM PRESSURE SENSOR
P0451 EVAP CONTROL SYSTEM PRESSURE SENSOR
Component DescriptionINFOID:0000000003771505
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 Diagn osis LogicINFOID:0000000003771506
NOTE:
If DTC P0451 is displayed with DTC P0643, first pe rform the trouble diagnosis for DTC P0643. Refer to
EC-285
.
DTC Confirmation ProcedureINFOID:0000000003771507
1. If DTC Confirmation Procedure has been previously conducted, always perform the following before con-
ducting the next step.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Turn ignition switch ON.
c. Turn ignition switch OFF and wait at least 10 seconds.
2. Start engine and wait at least 40 seconds. NOTE:
Do not depress accelerator pedal even slightly.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to EC-238, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771508
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
BBIA0443E
PBIB1207E
DTC No. Trouble diagnosis name DTC detecting condition Possible 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: December 20092009 QX56

P0550 PSP SENSOREC-277
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P0550 PSP SENSOR
Component DescriptionINFOID:0000000003771554
Power steering pressure (PSP) sensor (1) is installed to the power
steering high-pressure tube and detects a power steering load. This
sensor is a potentiometer which transforms the power steering load
into output voltage, and emits the voltage signal to the ECM. The
ECM controls the electric throttle
control actuator and adjusts the
throttle valve opening angle to increase the engine speed and
adjusts the idle speed for the increased load.
On Board Diagnosis LogicINFOID:0000000003771555
The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P0550 is displayed with DTC P0643, first pe rform the trouble diagnosis for DTC P0643. Refer to
EC-285
.
DTC Confirmation ProcedureINFOID:0000000003771556
1. If DTC Confirmation Procedure has been previously c onducted, always perform the following before con-
ducting the next step.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Turn ignition switch ON.
c. Turn ignition switch OFF and wait at least 10 seconds.
2. Start engine and let it idle for at least 5 seconds.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to EC-277, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771557
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-85, "Ground Inspection"
.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
BBIA0741E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0550
0550 Power steering pressure
sensor circuit An excessively low or high voltage from the
sensor is sent to ECM.  Harness or connectors
(The sensor circuit is open or shorted)
 Power steering pressure sensor
BBIA0354E
Revision: December 20092009 QX56

P0643 SENSOR POWER SUPPLYEC-285
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P0643 SENSOR POWER SUPPLY
On Board Diagnosis LogicINFOID:0000000003771567
This self-diagnosis has the on
e trip detection logic.
FAIL-SAFE MODE
When the malfunction is detected, ECM ent ers fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003771568
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always perform the following before conduct-
ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10V at idle.
1. Start engine and let it idle for 1 second.
2. Check DTC.
3. If DTC is detected, go to EC-285, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771569
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-85, "Ground Inspection"
.
OK or NG
OK >> GO TO 2.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0643
0643 Sensor power supply circuit
short ECM detects a voltage of power source
for sensor is excessively low or high.  Harness or connectors
(APP sensor 1 circuit is shorted.)
(PSP sensor circuit is shorted.)
(Battery current sensor circuit is shorted.)
(Refrigerant pressure se nsor circuit is short-
ed.)
(EVAP control system pressure sensor circuit
is shorted.)
 Accelerator pedal position sensor
 Power steering pressure sensor
 Refrigerant pressure sensor
 EVAP control system pressure sensor
Engine operation condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) b y the return
spring.
BBIA0354E
Revision: December 20092009 QX56