Nissan Frontier. Instruction — part 404

P0122, P0123 TP SENSOR

EC-187

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

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>> INSPECTION END

Component Inspection

INFOID:0000000009480837

THROTTLE POSITION SENSOR

1. Reconnect all harness connectors disconnected.
2. Perform

EC-123, "Throttle Valve Closed Position Learning"

.

3. Turn ignition switch ON.
4. Set shift lever to D (A/T) or 1st (M/T) position.
5. Check voltage between ECM terminals 37 (TP sensor 1 signal), 38 (TP sensor 2 signal) and ground under

the following conditions.

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

EM-27, "Exploded View"

.

7. Perform

EC-123, "Throttle Valve Closed Position Learning"

.

8. Perform

EC-124, "Idle Air Volume Learning"

.

Terminal

Accelerator pedal

Voltage

37
(Throttle position sensor 1)

Fully released

More than 0.36V

Fully depressed

Less than 4.75V

38
(Throttle position sensor 2)

Fully released

Less than 4.75V

Fully depressed

More than 0.36V

EC-188

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

P0125 ECT SENSOR

P0125 ECT SENSOR

Component Description

INFOID:0000000009480838

NOTE:

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

P0118. Refer to

EC-181

.

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 46 (Engine
coolant temperature sensor) and 52 (sensor 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:0000000009480839

DTC Confirmation Procedure

INFOID:0000000009480840

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

1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT.
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.

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-189

< DTC/CIRCUIT DIAGNOSIS >

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If it is below 10

°C (50°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 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-189, "Diagnosis Procedure"

.

WITH GST

Follow the procedure WITH CONSULT above.

Diagnosis Procedure

INFOID:0000000009480841

1.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

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

EC-149, "Ground Inspection"

.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace ground connections.

2.

CHECK ENGINE COOLANT TEMPERATURE SENSOR

Refer to

EC-189, "Component Inspection"

.

OK or NG

OK

>> GO TO 3.

NG

>> Replace engine coolant temperature sensor. Refer to

CO-23, "Exploded View"

.

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-23, "Removal and Installation Thermostat"

.

4.

CHECK INTERMITTENT INCIDENT

Refer to

GI-42, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000009480842

ENGINE COOLANT TEMPERATURE SENSOR

BBIA0614E

EC-190

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

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