2010 INFINITI QX56 check engine

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
Revision: April 20092010 QX56

P0117, P0118 ECT SENSOREC-123
< COMPONENT DIAGNOSIS > [VK56DE]
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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.
Revision: April 20092010 QX56

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
< COMPONENT DIAGNOSIS > [VK56DE]
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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

EC-126
< COMPONENT DIAGNOSIS >[VK56DE]
P0122, P0123 TP SENSOR
Refer to EC-85, "Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK THROTTLE POSITION SE NSOR 2 POWER SUPPLY CIRCUIT-I
1. Disconnect electric throttle control actuator harness connector.
2. Turn ignition switch ON.
3. Check voltage between electric throttle control actuator terminal 2 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 7.
NG >> GO TO 3.
3.CHECK THROTTLE POSITION SE NSOR 2 POWER SUPPLY CIRCUIT-II
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between electric thrott le control actuator terminal 2 and ECM terminal 47.
Refer to Wiring Diagram.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace open circuit.
4.CHECK THROTTLE POSITION SENS OR 2 POWER SUPPLY CIRCUIT-III
Check harness for short to power and short to ground, between the following terminals.
BBIA0354E
PBIB1480E
Voltage: Approximately 5 V
PBIB2065E
Continuity should exist.
ECM terminal Sensor terminal Reference Wiring Diagram
47 Electric throttle control actuator terminal 2 EC-435, "
Wiring Diagram - ENGINE
CONTROL SYSTEM -"91APP sensor terminal 6
Revision: April 20092010 QX56

EC-130
< COMPONENT DIAGNOSIS >[VK56DE]
P0125 ECT SENSOR
4. Check that “COOLAN TEMP/S” is above 31
°C (88° F).
If it is above 31° C (88°F), the test result will be OK.
If it is below 31 °C (88° F), go to following step.
5. Start engine and run it for 65 minutes at idle speed. If “COOLAN TEMP/S” increases to more than 31 °C (88° F) within 65 minutes, stop engine because
the test result will be OK.
6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to EC-130, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149144
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-130, "
Component Inspection".
OK or NG
OK >> GO TO 3.
NG >> Replace engine coolant temperature sensor.
3.CHECK THERMOSTAT OPERATION
When the engine is cold [lower than 70 °C (158° F)] condition, grasp lower radiator hose and confirm the engine
coolant does not flow.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace thermostat. Refer to CO-22, "
Removal and Installation".
4.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
Refer to EC-435, "
Wiring Diagram - ENGINE CONTROL SYSTEM -".
>> INSPECTION END
Component InspectionINFOID:0000000005149145
ENGINE COOLANT TEMPERATURE SENSOR
BBIA0354E
Revision: April 20092010 QX56

P0125 ECT SENSOREC-131
< COMPONENT DIAGNOSIS > [VK56DE]
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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

EC-132
< COMPONENT DIAGNOSIS >[VK56DE]
P0127 IAT SENSOR
P0127 IAT SENSOR
Component DescriptionINFOID:0000000005149146
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:0000000005149147
DTC Confirmation ProcedureINFOID:0000000005149148
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.
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.
1. Wait until engine coolant temperature is less than 96 °C (205 °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 96 °C (205 °F), turn ignition switch OFF and cool down
engine.
• Perform the following steps before engine coolant temperature is above 96 °C (205° F).
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: April 20092010 QX56