P0128

DTC P0128 THERMOSTAT FUNCTION




On Board Diagnosis Logic

DTC Confirmation Procedure

NOTE: If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next step.

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.

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 71 °C (160 °F).
- Before performing the following procedure, do not fill with the fuel.

WITH CONSULT-III
1. Turn A/C switch OFF.
2. Turn blower fan switch OFF.
3. Turn ignition switch ON.
4. Select "COOLAN TEMP/S" in "DATA MONITOR" mode with CONSULT-III.
5. Check the indication of "COOLAN TEMP/S".
If it is below 71 °C (160 °F), go to following step.
If it is above 71 °C (160 °F), cool down the engine to less than 71 °C (160 °F), then go to next step.

6. Start engine.
7. Wait at idle for a least 30 minutes.
If "COOLAN TEMP/S" increases to more than 71 °C (160 °F) within 30 minutes, turn ignition switch OFF because the test result will be OK.

8. Check 1st trip DTC.
9. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.

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

Step 1:

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.