Nissan Versa Sedan. Manual - part 300

P0125 ECT SENSOR

EC-199

< DTC/CIRCUIT DIAGNOSIS >

[HR16DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

P0125 ECT SENSOR

DTC Logic

INFOID:0000000009267100

DTC DETECTION LOGIC

NOTE:

• If DTC P0125 is displayed with P0116, first perform the trouble diagnosis for DTC P0116. Refer to 

EC-

192, "DTC Logic"

.

• If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or

P0118. Refer to 

EC-194, "DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting 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.

CHECK ENGINE COOLANT TEMPERATURE SENSOR FUNCTION

With CONSULT

1. Turn ignition switch ON.

2. Select “DATA MONITOR” mode of “ENGINE” using CONSULT.

3. Check that “COOLAN TEMP/S” is above 10

°C (50°F).

With GST

Follow the procedure “With CONSULT” above.
Is it above 5

°C (41°F)?

YES

>> INSPECTION END

NO

>> GO TO 3.

3.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT

1. Start engine and run it for 65 minutes at idle speed.

2. Check 1st tip DTC.

If “COOLAN TEMP/S” indication increases to more than 10

°C (50°F) within 65 minutes, stop engine

because the test result will be OK.

CAUTION:

Be careful not to overheat engine.

With GST

Follow the procedure “With CONSULT” above.
Is 1st trip DTC detected?

YES

>> Proceed to 

EC-199, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000009267101

1.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

DTC No.

Trouble diagnosis name

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P0125

ECT SENSOR
(Insufficient engine coolant 
temperature for closed loop 
fuel control)

• Voltage sent to ECM from the sensor is not 

practical, even when some time has passed 
after starting the engine.

• Engine coolant temperature is insufficient for 

closed loop fuel control.

• Harness or connectors

(High resistance in the circuit)

• Engine coolant temperature sensor
• Thermostat

EC-200

< DTC/CIRCUIT DIAGNOSIS >

[HR16DE]

P0125 ECT SENSOR

Check the engine coolant temperature sensor. Refer to

EC-193, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Replace engine coolant temperature sensor. Refer to 

CO-24, "Exploded View"

.

2.

CHECK THERMOSTAT OPERATION

When the engine is cold [lower than 70

°C (158°F)] condition, grasp lower radiator hose and confirm the engine

coolant does not flow.
Is the inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-45, "Intermittent Incident"

.

NO

>> Repair or replace thermostat. Refer to 

CO-21, "Removal and Installation"

.

Component Inspection

INFOID:0000000009620081

1.

CHECK ENGINE COOLANT TEMPERATURE (ECT) SENSOR

1. Turn ignition switch OFF.

2. Disconnect ECT sensor harness connector.

3. Remove ECT sensor.

4. Check resistance between ECT sensor terminals by heating

with hot water as shown in the figure.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace engine coolant temperature sensor. Refer to 

CO-24, "Exploded View"

.

ECT sensor

Condition

Resistance (k

Ω)

Terminal

1

2

Temperature [

°C (°F)]

20 (68)

2.10 - 2.90

50 (122)

0.68 - 1.00

90 (194)

0.236 - 0.260

JMBIA0080ZZ

P0127 IAT SENSOR

EC-201

< DTC/CIRCUIT DIAGNOSIS >

[HR16DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

P0127 IAT SENSOR

DTC Logic

INFOID:0000000009267103

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting 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.

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.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT

1. Wait until engine coolant temperature is less than 96

°C (205°F)

-

Turn ignition switch ON.

-

Select “DATA MONITOR” mode of “ENGINE” using CONSULT.

-

Check the engine coolant temperature.

-

If the engine coolant temperature is not less than 96

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

engine.

NOTE:

Perform the following steps before engine coolant temperature is above 96

°C (205°F).

2. Turn ignition switch ON.

3. Select “DATA MONITOR” mode of “ENGINE” using CONSULT

4. Start engine.

5. Hold vehicle speed at more than 70 km/h (43 MPH) for 100 consecutive seconds.

CAUTION:

Always drive vehicle at a safe speed.

6. Check 1st trip DTC.

With GST

Follow the procedure “With CONSULT” above.
Is 1st trip DTC detected?

YES

>> Proceed to 

EC-201, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000009267104

1.

CHECK INTAKE AIR TEMPERATURE SENSOR

Check the intake air temperature sensor. Refer to 

EC-189, "Component Inspection"

.

Is the inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-45, "Intermittent Incident"

.

DTC No.

Trouble diagnosis name

(Trouble diagnosis con-

tent)

DTC detecting condition

Possible cause

P0127

IAT SENSOR-B1
(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

(Intake air temperature sensor circuit is 
open or shorted)

• Intake air temperature sensor

EC-202

< DTC/CIRCUIT DIAGNOSIS >

[HR16DE]

P0127 IAT SENSOR

NO

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

EM-25, "Removal and

Installation"

.

Component Inspection

INFOID:0000000009620084

1.

CHECK INTAKE AIR TEMPERATURE SENSOR

1. Turn ignition switch OFF.

2. Disconnect mass air flow sensor harness connector.

3. Check resistance between mass air flow sensor terminals as per the following.

Is the inspection result normal?

YES

>> INSPECTION END

NO

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

EM-25, "Removal and

Installation"

.

Mass air flow sensor

Condition

Resistance (k

Ω)

Terminals

5

6

Temperature [

°C (°F)]

25 (77)

1.800 - 2.200