Infiniti G37 Coupe. Manual - part 500

P0112, P0113 IAT SENSOR

EC-181

< COMPONENT DIAGNOSIS >

[VQ37VHR]

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P0112, P0113 IAT SENSOR

Description

INFOID:0000000001734008

The intake air temperature sensor is built-into mass air flow sensor
(1). The sensor detects intake air temperature and transmits a signal
to the ECM.
The temperature sensing unit uses a thermistor which is sensitive to
the change in temperature. Electrical resistance of the thermistor
decreases in response to the temperature rise.
NOTE:
ECM uses only the intake air temperature sensor (bank 1) for engine
control and self-diagnosis. It does not use the intake air temperature
sensor (bank 2).

<Reference data>

*: These data are reference values and are measured between ECM terminal 67
(Intake air temperature sensor) and ground.

CAUTION:

Do not use ECM ground terminals when measuring input/output voltage. Doing
so may result in damage to the ECM’s transistor. Use a ground other than ECM
terminals, such as the ground.

DTC Logic

INFOID:0000000001734009

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing 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 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-182, "Diagnosis Procedure"

.

NO

>> INSPECTION END

PBIA9559J

Intake air temperature

°

C (

°

F)

Voltage*

V

Resistance

k

Ω

25 (77)

3.3

1.800 - 2.200

80 (176)

1.2

0.283 - 0.359

SEF012P

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0112

Intake air temperature sensor 
(bank 1) circuit low input

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

• Harness or connectors

(The sensor circuit is open or short-
ed.)

• Intake air temperature sensor

P0113

Intake air temperature sensor 
(bank 1) circuit high input

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

EC-182

< COMPONENT DIAGNOSIS >

[VQ37VHR]

P0112, P0113 IAT SENSOR

Diagnosis Procedure

INFOID:0000000001734010

1.

CHECK GROUND CONNECTION

1.

Turn ignition switch OFF.

2.

Check ground connection M95. Refer to Ground Inspection in 

GI-41, "Circuit Inspection"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace ground connection.

2.

CHECK INTAKE AIR TEMPERATURE SENSOR POWER SUPPLY CIRCUIT

1.

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

2.

Turn ignition switch ON.

3.

Check the voltage between mass air flow sensor (bank 1) harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> 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 the continuity between mass air flow sensor (bank 1) harness connector and ECM harness con-
nector.

4.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 4.

NO

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

4.

CHECK INTAKE AIR TEMPERATURE SENSOR

Refer to 

EC-182, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 5.

NO

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

5.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-38, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000001734011

1.

CHECK INTAKE AIR TEMPERATURE SENSOR

1.

Turn ignition switch OFF.

2.

Disconnect mass air flow sensor (bank 1) harness connector.

3.

Check resistance between mass air flow sensor (bank 1) terminals as follows.

MAF sensor (bank 1)

Ground

Voltage

Connector

Terminal

F31

2

Ground

Approx. 5

MAF sensor (bank 1)

ECM

Continuity

Connector

Terminal

Connector

Terminal

F31

1

F102

68

Existed

P0112, P0113 IAT SENSOR

EC-183

< COMPONENT DIAGNOSIS >

[VQ37VHR]

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Is the inspection result normal?

YES

>> INSPECTION END

NO

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

Terminals

Condition

Resistance

1 and 2

Temperature 

°

C (

°

F)

25 (77)

1.800 - 2.200 k

Ω

EC-184

< COMPONENT DIAGNOSIS >

[VQ37VHR]

P0117, P0118 ECT SENSOR

P0117, P0118 ECT SENSOR

Description

INFOID:0000000001734012

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 71
(Engine coolant temperature sensor) and ground.

CAUTION:

Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM’s transis-
tor. Use a ground other than ECM terminals, such as the ground.

DTC Logic

INFOID:0000000001734013

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-
ing 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.

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 tem-
perature sensor cir-
cuit 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 tem-
perature sensor cir-
cuit high input

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