P0128

DTC P0128 THERMOSTAT FUNCTION




On Board Diagnosis 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 stuck open.

DTC Confirmation Procedure

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.

TESTING CONDITION:
- For best results, perform at ambient temperature of -10 degrees C (14 degrees F) or higher.
- For best results, perform at engine coolant temperature of -10 degrees C (14 degrees F) to 60 degrees C (140 degrees F).

WITH CONSULT-II
1. Replace thermostat with new one.
Use only a genuine NISSAN thermostat as a replacement. If an incorrect thermostat is used, the MIL may come on.

2. Turn ignition switch ON.




3. Select "COOLAN TEMP/S" in "DATA MONITOR" mode with CONSULT-II.
4. Check that the "COOLAN TEMP/S" is above 60 degrees C (140 degrees F).
If it is below 60 degrees C (140 degrees F), go to following step.
If it is above 60 degrees C (140 degrees F), cool down the engine to less than 60 degrees C (140 degrees F), then retry from step 1.

5. Drive vehicle for 10 consecutive minutes under the following conditions.
VHCL SPEED SE 80 - 120 km/h (50 - 75 MPH)

If 1st trip DTC is detected, go to "Diagnostic Procedure".

WITH GST
Follow the procedure "WITH CONSULT-II".

Diagnostic Procedure:

Diagnostic Procedure

Component Inspection

ENGINE COOLANT TEMPERATURE SENSOR







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