DTC P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature): Procedure
WARNING: This page is about a different variant/trim than selected.
- CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0128)
- Connect the Techstream to the DLC3.
- Turn the ignition switch on (IG).
- Turn the tester on.
- Select the following menu items: Powertrain / Engine and ECT / Trouble Code.
- Read the DTCs.
Result
Display (DTC Output) Proceed to P0128 A P0128 and other DTCs B HINT:
If any DTCs other than P0128 are output, troubleshoot those DTCs first.
B → See step 5
A: Go to next step
- CHECK COOLING SYSTEM
- Check for defects in the cooling system that might cause the system to be too cold, such as abnormal radiator fan operation or any modifications.
NG → REPAIR OR REPLACE COOLING SYSTEM
OK: Go to next step
- INSPECT THERMOSTAT
- Remove the thermostat, refer to REMOVAL .
- Check the valve opening temperature of the thermostat.
Standard
80 to 84°C (176 to 183°F)
HINT:
In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.
- Reinstall the thermostat, refer to INSTALLATION .
NG → See step 6
OK → See step 4
- REPLACE ECM. Refer to COMPONENTS
- GO TO DTC CHART. Refer to DIAGNOSTIC TROUBLE CODE CHART
- REPLACE THERMOSTAT. Refer to COMPONENTS