Nissan Frontier. Manual - part 636

P0112, P0113 IAT SENSOR

EC-1115

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR MEXICO]

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P0112, P0113 IAT SENSOR

Component Description

INFOID:0000000009481761

The intake air temperature sensor is built-into the mass air flow sen-

sor (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 rise in temperature.

<Reference data>

*: This data is reference value and is measured between ECM terminal 34 (Intake air
temperature sensor) and ground.

CAUTION:

Never 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

INFOID:0000000009481762

DTC Confirmation Procedure

INFOID:0000000009481763

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

ducting the next step.

a. Turn ignition switch OFF and wait at least 10 seconds.
b. Turn ignition switch ON.
c. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON and wait at least 5 seconds.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to 

EC-1115, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000009481764

1.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

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
0112

Intake air tempera-
ture 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 tempera-
ture sensor circuit 
high input

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

EC-1116

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR MEXICO]

P0112, P0113 IAT SENSOR

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

EC-1094, "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-in) 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 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-1117, "Component Inspection"

.

OK or NG

OK

>> GO TO 5.

NG

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

EM-141, "Exploded

View"

.

BBIA0539E

BBIA0541E

Voltage: Approximately 5V

PBIB1169E

Continuity should exist.

P0112, P0113 IAT SENSOR

EC-1117

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR MEXICO]

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5.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-42, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000009481765

INTAKE AIR TEMPERATURE SENSOR

1. Check resistance between mass air flow sensor (1) terminals 5

and 6 under the following conditions.

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

sensor).

Intake air temperature 

°C (°F)

Resistance k

Ω

25 (77)

1.800 - 2.200

PBIA9559J

SEF012P

EC-1118

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR MEXICO]

P0117, P0118 ECT SENSOR

P0117, P0118 ECT SENSOR

Component Description

INFOID:0000000009481766

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>

*: This data is reference value and is measured between ECM terminal 73 (Engine
coolant temperature sensor) and ground.

CAUTION:

Never 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:0000000009481767

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 illuminates.

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 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
0118

Engine coolant tem-
perature sensor cir-
cuit high input

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