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Nissan Frontier. Manual - part 522

P0125 ECT SENSOR

EC-659

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

<Reference data>

2. If NG, replace engine coolant temperature sensor.

Engine coolant temperature [

°C (°F)]

Resistance (k

Ω

20 (68)

2.1 - 2.9

50 (122)

0.68 - 1.00

90 (194)

0.236 - 0.260

SEF012P

EC-660

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

P0127 IAT SENSOR

P0127 IAT SENSOR

Component Description

INFOID:0000000009481313

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.

<Reference data>

*: This data is reference value and is measured between ECM terminal 74 (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:0000000009481314

DTC Confirmation Procedure

INFOID:0000000009481315

NOTE:

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

ing the next step.
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.

CAUTION:

Always drive vehicle at a safe speed.

TESTING CONDITION:

This test may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road

test is expected to be easier, it is unnecessary to lift the vehicle.

WITH CONSULT

1. Wait until engine coolant temperature is less than 96

°C (205°F)

a. Turn ignition switch ON.
b. Select “DATA MONITOR” mode with CONSULT.
c.

Check the engine coolant temperature.

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

P0127
0127

Intake air temperature
too high

Rationally incorrect voltage from the sensor is
sent to ECM, compared with the voltage signal
from engine coolant temperature sensor.

• Harness or connectors

(The sensor circuit is open or shorted)

• Intake air temperature sensor

P0127 IAT SENSOR

EC-661

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE FOR USA AND CANADA]

d. If the engine coolant temperature is not less than 96

°C (205°F), turn ignition switch OFF and cool down

engine.

• Perform the following steps before engine coolant temperature is above 96

°C (205°F).

2. Turn ignition switch ON.
3. Select “DATA MONITOR” mode with CONSULT.
4. Start engine.
5. Hold vehicle speed at more than 70 km/h (43 MPH) for 100 consecutive seconds.
6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to

EC-661, "Diagnosis Procedure"

WITH GST

Follow the procedure “WITH CONSULT” above.

Diagnosis Procedure

INFOID:0000000009481316

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

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

EC-617, "Ground Inspection"

OK or NG

>> GO TO 2.

>> Repair or replace ground connections.