• Check Engine Light is on
• Poor fuel economy
• Heater not working properly
• Faulty thermostat
• Low engine coolant level
• Faulty engine coolant temperature sensor
Thermostat: A device that regulates the flow of coolant to maintain engine temperature.
Coolant: A fluid that absorbs heat from the engine and dissipates it through the radiator.
• P0116
• P0117
• P0118
Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
Your car's engine isn't getting warm enough, fast enough. It's like trying to play outside in the snow without a jacket.
The engine's coolant temperature is not reaching the expected level within a certain time after starting the engine.
The P0128 code indicates that the engine control module (ECM) has detected that the engine has not reached the required temperature level within a specified amount of time after starting the engine. This is often due to a thermostat that is stuck open or a faulty temperature sensor.
• Check the engine coolant level and fill if necessary.
• Inspect the thermostat for proper operation.
• Test the engine coolant temperature sensor.
• Replace the thermostat if it is faulty.
• Refill and bleed the cooling system if the coolant level is low.
• Replace the engine coolant temperature sensor if it is not working correctly.
• OBD-II scanner
• Coolant system pressure tester
• Wrench set
$150 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly check and maintain coolant levels.
• Replace the thermostat at recommended intervals.
• Ensure the cooling system is free of leaks.
Engine Performance
• Monitor engine temperature gauge regularly.
• Get regular vehicle maintenance.
• Seek professional diagnosis if unsure.
Thermostat replacements may be covered under powertrain warranty if the vehicle is still within the coverage period.
P0128 is a common code that often appears in colder climates where the engine struggles to reach operating temperature quickly.
Moderate – It won't immediately damage your car, but it should be addressed to ensure proper engine performance and fuel economy.
Driving with a malfunctioning thermostat can lead to increased emissions and may not comply with vehicle emission standards.
• Engine must be cold.
• Vehicle should be on a level surface.
The thermostat is typically located between the engine and the radiator, often near the top of the engine.
Q: Can I drive with a P0128 code?
A: Yes, but it's best to fix it soon to avoid poor fuel economy and potential engine issues.
Q: How do I know if my thermostat is stuck open?
A: If your engine takes a long time to warm up or doesn't reach normal operating temperature, the thermostat may be stuck open.
