P0128
DTC P0128 THERMOSTAT FUNCTIONOn 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 °C (14 °F) or higher.
- For best results, perform at engine coolant temperature of -10 °C (14 °F) to 60 °C (140 °F).
WITH CONSULT-II
1. Replace thermostat with new one. Refer to "THERMOSTAT AND THERMOSTAT HOUSING". 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 °C (140 °F).
If it is below 60 °C (140 °F), go to following step.
If it is above 60 °C (140 °F), cool down the engine to less than 60 °C (140 °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
1. Follow the procedure "WITH CONSULT-II" above.
Diagnostic Procedure (Step 1):
Diagnostic Procedure
Component Inspection
ENGINE COOLANT TEMPERATURE SENSOR
Check resistance as shown in the figure.
If NG, replace engine coolant temperature sensor.