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 5 seconds before conducting the next test.

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 70 °C (158 °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 70 °C (158 °F).
If it is below 70 °C (158 °F), go to following step.
If it is above 70 °C (158 °F), stop engine and cool down the engine to less than 70 °C (158 °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" below.

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

Diagnostic Procedure Step 1:

Diagnostic Procedure

Component Inspection

ENGINE COOLANT TEMPERATURE SENSOR




1. Check resistance as shown in the figure.




2. If NG, replace engine coolant temperature sensor.