Infiniti QX56 (JA60). Manual - part 367

EC-120

< COMPONENT DIAGNOSIS >

[VK56DE]

P0116 ECT SENSOR

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

P0117, P0118 ECT SENSOR

EC-121

< COMPONENT DIAGNOSIS >

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P0117, P0118 ECT SENSOR

Component Description

INFOID:0000000005149131

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.

<Reference data>

*: 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. Doing so may result in dam-

age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

On Board Diagnosis Logic

INFOID:0000000005149132

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 Name

DTC Detecting Condition

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.

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 Procedure

INFOID: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

P0117, P0118 ECT SENSOR

EC-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 Inspection

INFOID:0000000005149135

ENGINE COOLANT TEMPERATURE SENSOR

Voltage: Approximately 5 V

PBIB0080E

Continuity should exist.