Infiniti Q45. Manual - part 393

DTC P0112, P0113 IAT SENSOR

EC-211

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EC

DTC P0112, P0113 IAT SENSOR

PFP:22630

Component Description

NBS001SW

The intake air temperature sensor is built-into mass air flow sensor.
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.

<Reference data>

*: This data is reference value and is measured between ECM terminal 34 (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.

On Board Diagnosis Logic

NBS001SX

DTC Confirmation Procedure

NBS001SY

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.

 WITH CONSULT-II

1.

Turn ignition switch ON.

2.

Select “DATA MONITOR” mode with CONSULT-II.

3.

Wait at least 5 seconds.

4.

If 1st trip DTC is detected, go to 

EC-213, "Diagnostic Procedure"

.

 WITH GST

Follow the procedure WITH CONSULT-II above.

PBIB1604E

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
0112

Intake air 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.)

●

Intake air temperature sensor

P0113
0113

Intake air temperature sensor 
circuit high input

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

SEF058Y

EC-212

DTC P0112, P0113 IAT SENSOR

Wiring Diagram

NBS001SZ

TBWM0538E

DTC P0112, P0113 IAT SENSOR

EC-213

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Diagnostic Procedure

NBS001T0

1. 

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

2.

Loosen and retighten three ground screws on the body.
Refer to 

EC-154, "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) harness connector.

2.

Turn ignition switch ON.

3.

Check voltage between mass air flow sensor terminal 5 and
ground.

OK or NG

OK

>> GO TO 3.

NG

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

in harness or connectors.

PBIB2417E

PBIB2418E

Voltage: Approximately 5V

PBIB1169E

EC-214

DTC P0112, P0113 IAT SENSOR

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-213, "Diagnostic Procedure"

 .

OK or NG

OK

>> GO TO 5.

NG

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

5. 

CHECK INTERMITTENT INCIDENT

Refer to 

EC-145, "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT"

 .

>> INSPECTION END

Component Inspection

NBS001T1

INTAKE AIR TEMPERATURE SENSOR

1.

Check resistance between intake air temperature sensor termi-
nals 5 and 6 under the following conditions.

<Reference data>

2.

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

Removal and Installation

NBS001T2

MASS AIR FLOW SENSOR

Refer to 

EM-17, "AIR CLEANER AND AIR DUCT"

 .

Continuity should exist.

PBIB1604E

Intake air temperature 

°

C (

°

F)

Resistance k

Ω

25 (77)

1.800 - 2.200

SEF012P