2008 INFINITI QX56 ignition

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

P0112, P0113 IAT SENSOREC-119
< COMPONENT DIAGNOSIS > [VK56DE]
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Refer to
EC-86, "Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK INTAKE AIR TEMPERATURE SENSOR POWER SUPPLY CIRCUIT
1. Disconnect mass air flow sensor (with intake air temperature sensor) harness connector.
2. Turn ignition switch ON.
3. Check voltage between mass air flow sensor terminal 5 and ground.
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connectors.
3.CHECK INTAKE AIR TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between mass air flow sensor terminal 6 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 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to EC-120, "
Component Inspection".
OK or NG
OK >> GO TO 5.
NG >> Replace mass air flow sensor ( with intake air temperature sensor).
BBIA0354E
BBIA0368E
Voltage: Approximately 5V
PBIB1169E
Continuity should exist.
Revision: March 2010 2008 QX56

P0116 ECT SENSOREC-121
< COMPONENT DIAGNOSIS > [VK56DE]
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P0116 ECT SENSOR
Component DescriptionINFOID:0000000003760274
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 electrical 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 wh en measuring input/output voltage. Doing 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:0000000003760275
DTC Confirmation ProcedureINFOID:0000000003760276
NOTE:
•If DTC P0116 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117,
P0118. Refer to EC-125, "
DTC Confirmation Procedure".
• If DTC confirmation procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, 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.
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:
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
Revision: March 2010 2008 QX56

EC-122
< COMPONENT DIAGNOSIS >[VK56DE]
P0116 ECT SENSOR
Soak time changes depending on ambient ai
r 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-122, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000003760277
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-86, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-122, "
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-439, "
Wiring Diagram - ENGINE CONTROL SYSTEM -".
>> INSPECTION END
Component InspectionINFOID:0000000003760278
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.
BBIA0354E
PBIB2005E
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

P0117, P0118 ECT SENSOREC-125
< COMPONENT DIAGNOSIS > [VK56DE]
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DTC Confirmation ProcedureINFOID:0000000001351427
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 DTC.
4. If DTC is detected, go to EC-125, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351429
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-86, "
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
Revision: March 2010
2008 QX56

EC-126
< COMPONENT DIAGNOSIS >[VK56DE]
P0117, P0118 ECT SENSOR
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-126, "
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:0000000001351430
ENGINE COOLANT TEMPERATURE SENSOR
Voltage: Approximately 5V
PBIB0080E
Continuity should exist.
Revision: March 2010 2008 QX56