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Nissan Sentra Service Manual: P0128 Thermostat function

Nissan Sentra Service Manual / Engine / Engine control system / Dtc/circuit diagnosis / P0128 Thermostat function

DTC Logic

DTC DETECTION LOGIC

NOTE:

If DTC P0128 is displayed with DTC P0300, P0301, P0302, P0303 or P0304, first perform the trouble diagnosis for P0300, P0301, P0302, P0303 or P0304. Refer to EC-269, "DTC Logic".

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 being stuck open.

DTC No.

 CONSULT screen terms (Trouble diagnosis content)

 DTC detecting condition

 Possible cause
P0128 THERMSTAT FNCTN [Coolant thermostat (coolant temperature below thermostat regulating temperature)] The engine coolant temperature does not reach to specified temperature even though the engine has run long enough.
  • Thermostat
  • Leakage from sealing portion of thermostat
  • Engine coolant temperature sensor

DTC CONFIRMATION PROCEDURE

NOTE:

Never refuel before and during the following procedure.

1.PRECONDITIONING-1

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.PRECONDITIONING-2

With CONSULT


  1. Turn ignition switch ON.
  2. Check the following conditions


  1. Select “DATA MONITOR” mode of “ENGINE” using CONSULT.
  2. Check the following conditions:

Is the condition satisfied?


Is the condition satisfied? YES >> GO TO 3.

NO >> 1. Satisfy the condition.

2. GO TO 3.

3.PERFORM DTC CONFIRMATION PROCEDURE-1

With CONSULT


  1. Start engine.
  2. Drive the vehicle until the following condition is satisfied.

CAUTION:

Always drive vehicle at safe speed.

Drive the vehicle under the conditions instructed below until the difference between “COOLANT TEMP/S” and “FUEL T/TMP SE” becomes at least 26°C (47°F).


Drive the vehicle at 50 km/h (32 MPH) or more with the difference between “COOLANT TEMP/S” and “FUEL T/TMP SE” maintained at 26°C (47°F) or more.

NOTE:

Keep the accelerator pedal as steady as possible during cruising.

Drive the vehicle at 50 km/h (32 MPH) or more until “COOLANT TEMP/S” increases by 6°C (11°F).

NOTE:

Keep the accelerator pedal as steady as possible during cruising.

Is the condition satisfied? YES >> GO TO 4.

NO >> GO TO 1.

4.PERFORM DTC CONFIRMATION PROCEDURE-2

With CONSULT


  1. Drive the vehicle until the following condition is satisfied.

CAUTION:


CAUTION:

Always drive vehicle at safe speed.

  1. Check 1st trip DTC.

Is 1st trip DTC detected? YES >> Proceed to EC-208, "Diagnosis Procedure".

NO >> INSPECTION END

Diagnosis Procedure

1.CHECK ENGINE COOLANT TEMPERATURE SENSOR

Check the engine coolant temperature sensor. Refer to EC-208, "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

Check the thermostat. Refer to CO-21, "Removal and Installation of Thermostat".

Is the inspection result normal? YES >> INSPECTION END

NO >> Replace thermostat.

Component Inspection

1.CHECK ENGINE COOLANT TEMPERATURE SENSOR

  1. Turn ignition switch OFF.
  2. Disconnect engine coolant temperature sensor harness connector.
  3. Remove engine coolant temperature sensor.
  4. Check resistance between engine coolant temperature sensor terminals by heating with hot water as shown in the figure.


Is the inspection result normal?


Is the inspection result normal? YES >> INSPECTION END

NO >> Replace engine coolant temperature sensor. Refer to CO-24, "Exploded View".

P0127 IATSensor
DTC Logic DTC DETECTION LOGIC DTC No. CONSULT screen terms (Trouble diagnosis content) DTC detecting condition Possible cause P0127 IAT SENSOR-B1 (Intake air temper ...

P0130 A/F Sensor 1
DTC Logic DTC DETECTION LOGIC To judge the malfunction, the diagnosis checks that the A/F signal computed by ECM from the A/F sensor 1 signal fluctuates according to fuel feedback control. ...

Other materials:

ECU diagnosis information
TCM Reference Value CONSULT DATA MONITOR STANDARD VALUE NOTE: The following table includes information (items) inapplicable to this vehicle. For information (items) applicable to this vehicle, refer to CONSULT display items. In CONSULT, electric shift timing or lock-up timing, i.e. op ...

Connector symbols
Most of connector symbols in wiring diagrams are shown from the terminal side. Connector symbols shown from the terminal side are enclosed by a single line and followed by the direction mark. Connector symbols shown from the harness side are enclosed by a double line and followed by the ...

Front regulator
Exploded View Front door panel Front door glass channel front Front door glass regulator Front door glass regulator motor Front door glass channel rear Front door glass Front door glass rubber run Removal and Installation REMOVAL WARNING: Before servicing, turn ignition ...

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