Infiniti FX35 / FX45. Manual - part 358

 

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Infiniti FX35 / FX45. Manual - part 358

 

 

DTC P0117, P0118 ECT SENSOR

EC-193

< SERVICE INFORMATION >

[VQ35DE]

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DTC P0117, P0118 ECT SENSOR

Component Description

INFOID:0000000001326013

The engine coolant temperature (ECT) 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 thermistor decreases as temperature increases.

<Reference data>

*: This data is reference values 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:0000000001326014

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

-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 tem-
perature sensor cir-
cuit low input

An excessively low voltage from the sensor is 
sent to ECM.

• Harness or connectors

(Engine coolant temperature sensor circuit is 
open or shorted.)

• Engine coolant temperature sensor 

P0118
0118

Engine coolant tem-
perature sensor cir-
cuit high input

An excessively high voltage from the sensor is 
sent to ECM.

EC-194

< SERVICE INFORMATION >

[VQ35DE]

DTC P0117, P0118 ECT SENSOR

DTC Confirmation Procedure

INFOID:0000000001326015

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.
1.

Turn ignition switch ON and wait at least 5 seconds.

2.

Check DTC.

3.

If DTC is detected, go to 

EC-195, "Diagnosis Procedure"

.

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.

DTC P0117, P0118 ECT SENSOR

EC-195

< SERVICE INFORMATION >

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Wiring Diagram

INFOID:0000000001326016

Diagnosis Procedure

INFOID:0000000001326017

1.

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

TBWM0289E

EC-196

< SERVICE INFORMATION >

[VQ35DE]

DTC P0117, P0118 ECT SENSOR

2.

Loosen and retighten ground screw on the body. Refer to 

EC-144, "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 harness
connector.

2.

Turn ignition switch ON.

3.

Check voltage between ECT sensor terminal 1 and ground with
CONSULT-III or tester.

OK or NG

OK

>> GO TO 3.

NG

>> Repair open circuit or short to ground or short to power

in harness or connectors.

3.

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 4.

NG

>> Repair open circuit or short to ground or short to power in harness or connectors.

4.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

Refer to 

EC-197, "Component Inspection"

.

OK or NG

OK

>> GO TO 5.

NG

>> Replace engine coolant temperature sensor.

PBIB2625E

PBIB1563E

Voltage: Approximately 5V

PBIB0080E

Continuity should exist.

 

 

 

 

 

 

 

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