P0128

DTC P0128: Coolant Thermostat (Coolant Temperature below Thermostat Regulating Temperature)

Wiring Diagram:

Wiring Diagram

DTC Detecting Condition / Trouble Code:

DTC Detecting Condition and Trouble Area

DTC Confirmation Procedure

WARNING:
- When performing a road test, select a place where there is no traffic or possibility of a traffic accident and be very careful during testing to avoid occurrence of an accident.
- Road test should be carried out with 2 persons, a driver and a tester, on a level road.

NOTE: Check to make sure that the following conditions are satisfied when using this "DTC Confirmation Procedure".
- Intake air temp.: -8 °C (18 °F) or higher
- Engine coolant temp.: -8 - 80 °C (18 - 176 °F)
- Altitude (barometric pressure): 2400 m, 8000 ft or less (560 mmHg (75 kPa) or more)

1. Connect scan tool to DLC with ignition switch OFF.
2. Turn ON ignition switch and clear DTC, pending DTC and freeze frame data by using scan tool and start engine.
3. Increase vehicle speed to 80 - 100 km/h (50 - 60 mph).
4. Keep driving above vehicle speed for 10 min. or more (or until engine coolant temperature reaches 80 °C (176 °F)) (Change of vehicle speed is permitted in this step).
5. stop vehicle.
6. Check DTC and pending DTC by using scan tool.

Step 1:

Step 2 - 4:

DTC Troubleshooting