Infiniti FX35 / FX45. Manual - part 504

DTC P0112, P0113 IAT SENSOR

EC-777

< SERVICE INFORMATION >

[VK45DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Refer to 

EC-723, "Ground Inspection"

.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace ground connections.

2.

CHECK INTAKE AIR TEMPERATURE SENSOR POWER SUPPLY CIRCUIT

1.

Disconnect mass air flow sensor (intake air temperature sensor
is built-into) (1) harness connector.

2.

Turn ignition switch ON.

3.

Check voltage between mass air flow sensor terminal 5 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 INTAKE AIR TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check harness continuity between mass air flow sensor terminal 6 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 INTAKE AIR TEMPERATURE SENSOR

Refer to 

EC-778, "Component Inspection"

.

OK or NG

OK

>> GO TO 5.

NG

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

PBIB2195E

PBIB3230E

Voltage: Approximately 5V

PBIB1169E

Continuity should exist.

EC-778

< SERVICE INFORMATION >

[VK45DE]

DTC P0112, P0113 IAT SENSOR

5.

CHECK INTERMITTENT INCIDENT

Refer to 

EC-717

.

>> INSPECTION END

Component Inspection

INFOID:0000000001326608

INTAKE AIR TEMPERATURE SENSOR

1.

Check resistance between intake air temperature terminals 5
and 6 under the following conditions.

2.

If NG, replace mass air flow sensor (with intake air temperature
sensor).

Removal and Installation

INFOID:0000000001326609

MASS AIR FLOW SENSOR

Refer to 

EM-173

.

Intake air temperature 

°

C (

°

F)

Resistance k

Ω

25 (77)

1.800 - 2.200

PBIB1604E

SEF012P

DTC P0117, P0118 ECT SENSOR

EC-779

< SERVICE INFORMATION >

[VK45DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

DTC P0117, P0118 ECT SENSOR

Component Description

INFOID:0000000001326610

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 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:0000000001326611

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 conditions.
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-780

< SERVICE INFORMATION >

[VK45DE]

DTC P0117, P0118 ECT SENSOR

DTC Confirmation Procedure

INFOID:0000000001326612

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-781, "Diagnosis Procedure"

.