Infiniti FX35 / FX45. Manual - part 507

DTC P0122, P0123 TP SENSOR

EC-789

< SERVICE INFORMATION >

[VK45DE]

C

D

E

F

G

H

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J

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EC

N

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O

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-663, "Throttle Valve Closed Position Learning"

.

8.

Perform 

EC-663, "Idle Air Volume Learning"

.

Removal and Installation

INFOID:0000000001326624

ELECTRIC THROTTLE CONTROL ACTUATOR

Refer to 

EM-175

.

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

PBIB1530E

EC-790

< SERVICE INFORMATION >

[VK45DE]

DTC P0125 ECT SENSOR

DTC P0125 ECT SENSOR

Component Description

INFOID:0000000001326625

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

EC-779

.

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>

*: These data are reference values and are 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:0000000001326626

DTC Confirmation Procedure

INFOID:0000000001326627

CAUTION:

Be careful not to overheat engine.
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-III

1.

Turn ignition switch ON.

2.

Select “DATA MONITOR” mode with CONSULT-III.

3.

Check that “COOLAN TEMP/S” is above 10

°

C (50

°

F).

If it is above 10

°

C (50

°

F), the test result will be OK.

If it is below 10

°

C (50

°

F), go to following step.

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

DTC P0125 ECT SENSOR

EC-791

< SERVICE INFORMATION >

[VK45DE]

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4.

Start engine and run it for 65 minutes at idle speed.
If “COOLAN TEMP/S” increases to more than 10

°

C (50

°

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-791, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT-III” above.

Diagnosis Procedure

INFOID:0000000001326628

1.

CHECK GROUND CONNECTIONS

1.

Turn ignition switch OFF.

2.

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

EC-723, "Ground Inspection"

.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace ground connections.

2.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

Refer to 

EC-791, "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-52

.

4.

CHECK INTERMITTENT INCIDENT

Refer to 

EC-717

.

Refer to 

EC-781, "Wiring Diagram"

.

>> INSPECTION END

Component Inspection

INFOID:0000000001326629

ENGINE COOLANT TEMPERATURE SENSOR

PBIB2195E

EC-792

< SERVICE INFORMATION >

[VK45DE]

DTC 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.

Removal and Installation

INFOID:0000000001326630

ENGINE COOLANT TEMPERATURE SENSOR

Refer to 

CO-52

.

PBIB2005E

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