2009 INFINITI QX56 engine

P0116 ECT SENSOREC-117
< COMPONENT DIAGNOSIS > [VK56DE]
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P0116 ECT SENSOR
Component DescriptionINFOID:0000000003771369
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:0000000003771370
DTC Confirmation ProcedureINFOID:0000000003771371
NOTE:
If DTC P0116 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117,
P0118. Refer to EC-121, "DTC Confirmation Procedure"
.
 If DTC confirmation procedure has been previously c onducted, 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, 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.
SEF594K
Engine coolant
temperature °C ( °F)] Voltage* (V) Resistance (k
Ω)
− 10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.1 - 2.9
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible 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: December 20092009 QX56

EC-118
< COMPONENT DIAGNOSIS >[VK56DE]
P0116 ECT SENSOR
CAUTION:
Never turn ignition switch
ON during the soaking time.
NOTE:
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-118, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771372
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-118, "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-432, "Wiring Diagram - ENGINE CONTROL SYSTEM -"
.
>> INSPECTION END
Component InspectionINFOID:0000000003771373
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.
BBIA0354E
PBIB2005E
Revision: December 20092009 QX56

P0116 ECT SENSOREC-119
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2. If NG, replace engine coolant temperature sensor.
Engine coolant temperature
°C ( °F)] Resistance (k Ω)
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
SEF012P
Revision: December 20092009 QX56

EC-120
< COMPONENT DIAGNOSIS >[VK56DE]
P0117, P0118 ECT SENSOR
P0117, P0118 ECT SENSOR
Component DescriptionINFOID:0000000003771374
The engine coolant temperature sens
or 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 in put/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:0000000003771375
These self-diagnoses have the one trip detection logic.
FAIL-SAFE MODE
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 (k
Ω)
–10 (14) 4.4 7.0 - 11.4 20 (68) 3.5 2.1 - 2.9
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260
SEF012P
DTC No. Trouble Diagnosis Na
me DTC 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: December 20092009 QX56

P0117, P0118 ECT SENSOREC-121
< COMPONENT DIAGNOSIS > [VK56DE]
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DTC Confirmation ProcedureINFOID:0000000003771376
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. Turn ignition switch ON.
3. Wait at least 5 seconds.
4. Check DTC.
5. If DTC is detected, go to EC-121, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771377
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: December 20092009 QX56

EC-122
< 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 s ensor 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-122, "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:0000000003771378
ENGINE COOLANT TEMPERATURE SENSOR
Voltage: Approximately 5V
PBIB0080E
Continuity should exist.
Revision: December 20092009 QX56

P0117, P0118 ECT SENSOREC-123
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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 (k Ω)
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
SEF012P
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