check engine INFINITI QX56 2010 Factory Service Manual

P0101 MAF SENSOREC-105
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1. Start engine and warm it up to normal operating temperature.
If engine cannot be started, go to EC-106, "
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-106, "
Diagnosis Procedure".
If OK, go to following step.
6. Maintain the following conditions for at least 10 consecutive seconds.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to EC-106, "
Diagnosis Procedure".
Overall Function CheckINFOID:0000000005149113
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-106, "
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
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EC-108
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P0101 MAF SENSOR
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:0000000005149115
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 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.
Condition MAS A/F SE-B1 (V)
Ignition switch ON (Engine stopped.) Approx. 0.4
Idle (Engine is warmed-up to normal
operating temperature.) 0.9 - 1.3
2,500 rpm (Engine is warmed-up to
normal operating temperature.) 1.7 - 2.1
Idle to about 4,000 rpm 0.9 - 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.) 0.9 - 1.3
2,500 rpm (Engine is warmed-up to
normal operating temperature.) 1.7 - 2.1
Idle to about 4,000 rpm 0.9 - 1.3 to Approx. 2.4*
PBIB1106E
Revision: April 20092010 QX56

EC-110
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P0102, P0103 MAF SENSOR
P0102, P0103 MAF SENSOR
Component DescriptionINFOID:0000000005149116
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 supplied 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 Diagn osis LogicINFOID:0000000005149117
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.
DTC Confirmation ProcedureINFOID:0000000005149118
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
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.
PROCEDURE FOR DTC P0102
1. Start engine and wait at least 5 seconds.
2. Check DTC.
3. If DTC is detected, go to E C - 111 , "
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 E C - 111 , "
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 E C - 111 , "
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.
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P0102, P0103 MAF SENSOREC-113
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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.
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 malfunctioning 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 har ness 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.) 0.9 - 1.3
2,500 rpm (Engine is warmed-up to
normal operating temperature.) 1.7 - 2.1
Idle to about 4,000 rpm 0.9 - 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.) 0.9 - 1.3
2,500 rpm (Engine is warmed-up to
normal operating temperature.) 1.7 - 2.1
Idle to about 4,000 rpm 0.9 - 1.3 to Approx. 2.4*
PBIB1106E
Revision: April 20092010 QX56

EC-118
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P0116 ECT SENSOR
P0116 ECT SENSOR
Component DescriptionINFOID:0000000005149126
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:0000000005149127
NOTE:
If DTC P0116 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117,
P0118. Refer to EC-122, "
DTC Confirmation Procedure".
DTC Confirmation ProcedureINFOID:0000000005149128
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
• Turn ignition switch OFF and wait at least 10 seconds.
• Turn ignition switch ON.
• Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following pro cedure, do not fill with the fuel.
1. Start engine and warm it up to normal operating temperature.
2. Rev engine up to 2,000 rpm for more than10 minutes.
3. Move the vehicle to a cool place, then stop engine and turn ignition switch OFF.
4. Check resistance between “fuel level sensor and fuel pump” terminals 3 and 4.
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 name DTC detecting conditionPossible cause
P0116
0116 Engine coolant tempera-
ture sensor circuit range/
performance Engine coolant temperature signal from engine
coolant temperature sensor does not fluctuate,
even when some time has passed after starting
the engine with pre-warming up condition. • Harness or connectors
(High or low resistance in the circuit)
• Engine coolant temperature sensor
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P0116 ECT SENSOREC-119
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5. Soak the vehicle until the resistance between “fuel
level sensor and fuel pump” terminals 3 and 4
becomes 0.5 k Ω higher than the value measured before soaking.
CAUTION:
Never turn ignition switch ON during the soaking time.
NOTE:
Soak time changes depending on ambient air temperature. It may take several hours.
6. Start engine and let it idle for 5 minutes.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to EC-119, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149129
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.
2.CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-119, "
Component Inspection".
OK or NG
OK >> GO TO 3.
NG >> Replace engine coolant temperature sensor.
3.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
For Wiring Diagram, refer to EC-435, "
Wiring Diagram - ENGINE CONTROL SYSTEM -".
>> INSPECTION END
Component InspectionINFOID:0000000005149130
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.
BBIA0354E
PBIB2005E
Revision: April 20092010 QX56

EC-122
< COMPONENT DIAGNOSIS >[VK56DE]
P0117, P0118 ECT SENSOR
DTC Confirmation Procedure
INFOID:0000000005149133
1. If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting 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. Turn ignition switch ON.
3. Wait at least 5 seconds.
4. Check DTC.
5. If DTC is detected, go to EC-122, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149134
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.
2.CHECK ECT SENSOR POWER SUPPLY CIRCUIT
1. Disconnect engine coolant temperature (ECT) sensor (1) harness connector.
2. Turn ignition switch ON.
BBIA0354E
1. Engine coolant temperature (ETC) sensor 2. Intake manifold
BBIA0775E
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P0117, P0118 ECT SENSOREC-123
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3. Check voltage between ECT sensor (1) terminal 1 and ground
with CONSULT-III or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3.DETECT MALFUNCTIONING RART
Check the following.
• Harness connector F26, F101
• Harness for open or short between ECM and engine coolant temperature sensor
>> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK ECT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECT sensor terminal 2 and ECM terminal 67. Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
• Harness connector F26, F101
• Harness for open and short between ECT sensor and ECM
>> Repair open circuit or short to ground or short to power in harness or connectors.
6.CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-123, "
Component Inspection".
OK or NG
OK >> GO TO 7.
NG >> Replace engine coolant temperature sensor.
7.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
>> INSPECTION END
Component InspectionINFOID:0000000005149135
ENGINE COOLANT TEMPERATURE SENSOR
Voltage: Approximately 5 V
PBIB0080E
Continuity should exist.
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EC-124
< COMPONENT DIAGNOSIS >[VK56DE]
P0117, P0118 ECT SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.
2. If NG, replace engine coolant temperature sensor.
PBIB2005E
Engine coolant temperature °C ( °F)] Resistance (kΩ)
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
SEF012P
Revision: April 20092010 QX56

P0122, P0123 TP SENSOREC-125
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P0122, P0123 TP SENSOR
Component DescriptionINFOID:0000000005149136
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 Diagnosis LogicINFOID:0000000005149137
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, ECM ent ers fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000005149138
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
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 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-125, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149139
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: April 20092010 QX56