Infiniti FX35, FX50 (S51). Manual - part 812

P0112, P0113 IAT SENSOR

EC-789

< DTC/CIRCUIT DIAGNOSIS >

[VK50VE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace mass air flow sensor (bank 1) (with intake air temperature sensor).

Terminals

Condition

Resistance (k

Ω

)

1 and 2

Temperature [

°

C (

°

F)]

25 (77)

1.800 - 2.200

EC-790

< DTC/CIRCUIT DIAGNOSIS >

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P0116 ECT SENSOR

P0116 ECT SENSOR

Description

INFOID:0000000005237267

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>

*: These data are reference values and are measured between ECM terminals 24
(Engine coolant temperature sensor) and 23 (Sensor ground).

DTC Logic

INFOID:0000000005237268

DTC DETECTION LOGIC

NOTE:
If DTC P0116 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117,
P0118. Refer to 

EC-792, "DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next test.
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.

TEST CONDITION:
Before performing the following procedure, do not add fuel.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Start engine and warm it up to normal operating temperature.

2.

Rev engine up to 2,000 rpm for more than 10 minutes.

3.

Move the vehicle to a cool place, then stop engine.

SEF594K

Engine coolant temperature 

[

°

C (

°

F)]

Voltage* (V)

Resistance (k

Ω

)

−

10 (14)

4.4

7.0 - 11.4

20 (68)

3.5

2.37 - 2.63

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

Engine coolant temperature 
sensor circuit range/perfor-
mance

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

P0116 ECT SENSOR

EC-791

< DTC/CIRCUIT DIAGNOSIS >

[VK50VE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

4.

Check resistance between “fuel level sensor unit and fuel pump (main)” terminals 4 and 5.

5.

Soak the vehicle until the resistance between “fuel level sensor unit and fuel pump (main)” terminals 4 and
5 becomes 0.5 k

Ω

 higher than the value measured before soaking.

CAUTION:

Never turn ignition switch ON during soaking.
NOTE:
Soak time changes depending on ambient air temperature. It may take several hours.

6.

Start engine and let it idle for 20 minutes.

7.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-791, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000005237269

1.

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

2.

Check ground connection M95. Refer to Ground Inspection in 

GI-39, "Circuit Inspection"

.

Is the inspection result normal?

OK

>> GO TO 2.

NG

>> Repair or replace ground connections.

2.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

Refer to 

EC-791, "Component Inspection"

.

Is the inspection result normal?

OK

>> GO TO 3.

NG

>> Replace engine coolant temperature sensor.

3.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-36, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000005237270

1.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

1.

Turn ignition switch OFF.

2.

Disconnect engine coolant temperature sensor harness connector.

3.

Remove engine coolant temperature sensor.

4.

Check resistance between engine coolant temperature sensor
terminals by heating with hot water as shown in the figure.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace engine coolant temperature sensor.

Terminals

Condition

Resistance (k

Ω

)

1 and 2

Temperature [

°

C (

°

F)]

20 (68)

2.37 - 2.63

50 (122)

0.68 - 1.00

90 (194)

0.236 - 0.260

JMBIA0080ZZ

EC-792

< DTC/CIRCUIT DIAGNOSIS >

[VK50VE]

P0117, P0118 ECT SENSOR

P0117, P0118 ECT SENSOR

Description

INFOID:0000000005237271

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>

*: These data are reference values and are measured between ECM terminals 24
(Engine coolant temperature sensor) and 23 (Sensor ground).

DTC Logic

INFOID:0000000005237272

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next test. 
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.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Turn ignition switch ON and wait at least 5 seconds.

2.

Check DTC.

Is DTC detected?

YES

>> Go to 

EC-793, "Diagnosis Procedure"

.

NO

>> INSPECTION END

SEF594K

Engine coolant temperature 

[

°

C (

°

F)]

Voltage* (V)

Resistance (k

Ω

)

−

10 (14)

4.4

7.0 - 11.4

20 (68)

3.5

2.37 - 2.63

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

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

Engine coolant temperature 
sensor circuit high input

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