Nissan Pathfinder (2008 year). Manual - part 252

P0122, P0123 TP SENSOR

EC-133

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>> INSPECTION END

Component Inspection

INFOID:0000000001370711

THROTTLE POSITION SENSOR

1.

Reconnect all harness connectors disconnected.

2.

Perform 

EC-26, "Throttle Valve Closed Position Learning"

.

3.

Turn ignition switch ON.

4.

Set selector lever to D position. 

5.

Check voltage between ECM terminals 50 (TP sensor 1 signal),
69 (TP sensor 2 signal) and ground under the following condi-
tions.

6.

If NG, replace electric throttle control actuator and go to the next
step.

7.

Perform 

EC-26, "Throttle Valve Closed Position Learning"

.

8.

Perform 

EC-26, "Idle Air Volume Learning"

.

Terminal

Accelerator pedal

Voltage

50
(Throttle position sensor 1)

Fully released

More than 0.36V

Fully depressed

Less than 4.75V

69
 (Throttle position sensor 2)

Fully released

Less than 4.75V

Fully depressed

More than 0.36V

PBIB1608E

EC-134

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P0125 ECT SENSOR

P0125 ECT SENSOR

Component Description

INFOID:0000000001375756

NOTE:
If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or
P0118. Refer to 

EC-126, "Component Description"

.

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:

Do not 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:0000000001375757

DTC Confirmation Procedure

INFOID:0000000001375758

CAUTION:

Be careful not to overheat engine.
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.

 WITH CONSULT-III

1.

Turn ignition switch ON.

2.

Select “DATA MONITOR” mode with CONSULT-III.

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

P0125
0125

Insufficient engine cool-
ant 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

P0125 ECT SENSOR

EC-135

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3.

Check that “COOLAN TEMP/S” is above 20

°

C (68

°

F).

If it is above 20

°

C (68

°

F), the test result will be OK.

If it is below 20

°

C (68

°

F), go to following step.

4.

Start engine and run it for 65 minutes at idle speed.
If “COOLAN TEMP/S” increases to more than 20

°

C (68

°

F) within 65 minutes, stop engine because

the test result will be OK.

5.

Check 1st trip DTC.

6.

If 1st trip DTC is detected, go to 

EC-135, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT-III” above.

Diagnosis Procedure

INFOID:0000000001375759

1.

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

2.

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

EC-96, "Ground Inspection"

.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace ground connections.

2.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

Refer to 

EC-135, "Component Inspection"

.

OK or NG

OK

>> GO TO 3.

NG

>> Replace engine coolant temperature sensor.

3.

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.

OK or NG

OK

>> GO TO 4.

NG

>> Repair or replace thermostat. Refer to 

CO-26, "Removal and Installation"

.

4.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-47, "Work Flow"

.

>> INSPECTION END

Component Inspection

INFOID:0000000001375760

ENGINE COOLANT TEMPERATURE SENSOR

BBIA0539E

EC-136

< COMPONENT DIAGNOSIS >

[VQ40DE]

P0125 ECT SENSOR

1.

Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.

<Reference data>

2.

If NG, replace engine coolant temperature sensor.

PBIB2005E

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

P0127 IAT SENSOR

EC-137

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P0127 IAT SENSOR

Component Description

INFOID:0000000001375761

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 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

INFOID:0000000001375762

DTC Confirmation Procedure

INFOID:0000000001375763

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-III

1.

Wait until engine coolant temperature is less than 90

°

C (194

°

F)

a.

Turn ignition switch ON.

b.

Select “DATA MONITOR” mode with CONSULT-III.

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

EC-138

< COMPONENT DIAGNOSIS >

[VQ40DE]

P0127 IAT SENSOR

d.

If the engine coolant temperature is not less than 90

°

C (194

°

F), turn ignition switch OFF and cool down

engine.
• Perform the following steps before engine coolant temperature is above 90

°

C (194

°

F).

2.

Turn ignition switch ON.

3.

Select “DATA MONITOR” mode with CONSULT-III.

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-138, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT-III” above.

Diagnosis Procedure

INFOID:0000000001375764

1.

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

2.

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

EC-96, "Ground Inspection"

.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace ground connections.

2.

CHECK INTAKE AIR TEMPERATURE SENSOR

Refer to 

EC-138, "Component Inspection"

.

OK or NG

OK

>> GO TO 3.

NG

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

3.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-47, "Work Flow"

.

>> INSPECTION END

Component Inspection

INFOID:0000000001375765

INTAKE AIR TEMPERATURE SENSOR

1.

Check resistance between intake air temperature sensor (1) ter-
minals 5 and 6 under the following conditions.

2.

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

BBIA0539E

Intake air temperature 

°

C (

°

F)

Resistance k

Ω

25 (77)

1.800 - 2.200

PBIA9559J

P0127 IAT SENSOR

EC-139

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SEF012P

EC-140

< COMPONENT DIAGNOSIS >

[VQ40DE]

P0128 THERMOSTAT FUNCTION

P0128 THERMOSTAT FUNCTION

On Board Diagnosis Logic

INFOID:0000000001375767

Engine coolant temperature has not risen enough to open the thermostat even though the engine has run long
enough.
This is due to a leak in the seal or the thermostat stuck open.

DTC Confirmation Procedure

INFOID:0000000001605743

NOTE:
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.

TESTING CONDITION:
• For best results, perform at ambient temperature of –10

°

C (14

°

F) or higher.

• For best results, perform at engine coolant temperature of –10

°

C (14

°

F) to 71

°

C (160

°

F).

• Before performing the following procedure, do not fill with the fuel.

 WITH CONSULT-III

1.

Turn A/C switch OFF.

2.

Turn blower fan switch OFF.

3.

Turn ignition switch ON.

4.

Select “COOLAN TEMP/S” in “DATA MONITOR” mode with CONSULT-III.

5.

Check the indication of “COOLAN TEMP/S”.
If it is below 71

°

C (160

°

F), go to following step.

If it is above 71

°

C (160

°

F), cool down the engine to less than 71

°

C (160

°

F), then go to next step.

6.

Start engine.

7.

Wait at idle for a least 30 minutes.
If “COOLAN TEMP/S” increases to more than 71

°

C (160

°

F) within 30 minutes, turn ignition switch

OFF because the test result will be OK.

8.

Check 1st trip DTC.

9.

If 1st trip DTC is detected, go to 

EC-140, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT-III” above.

Diagnosis Procedure

INFOID:0000000001375769

1.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

Refer to 

EC-140, "Component Inspection"

.

OK or NG

OK

>> INSPECTION END

NG

>> Replace engine coolant temperature sensor.

Component Inspection

INFOID:0000000001375770

ENGINE COOLANT TEMPERATURE SENSOR

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0128
0128

Thermostat function

The engine coolant temperature does not reach 
to specified temperature even though the en-
gine has run long enough.

• Thermostat
• Leakage from sealing portion of thermo-

stat

• Engine coolant temperature sensor