P0116 — Engine Coolant Temperature Circuit Range/Performance Problem
Drive with caution — fix soon.
What P0116 means
This code means the coolant temperature sensor is functioning but reporting values that don't make sense to the computer, such as warming up too slowly or reading outside the expected range. Common causes include a stuck thermostat, a failing ECT sensor, or low coolant, and fixes often involve replacing the thermostat or sensor. It's a moderate code that's usually straightforward to diagnose and repair.
Common symptoms
- Check engine light is on
- Engine takes too long to reach operating temperature
- Poor fuel economy
- Heater blowing lukewarm air
- Temperature gauge reading lower or higher than normal
Common causes
- Stuck-open thermostat keeping the engine cool
- Failing engine coolant temperature sensor
- Low coolant level or trapped air in the system
- Wiring resistance affecting the sensor signal
- Faulty cooling system component skewing readings
Typical repair cost
$100 – $350
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0116 code?
Usually yes for short trips, since the sensor is reading off rather than dead. You might notice slower warm-up or worse mileage, but it's generally safe. Because it ties into cooling, still watch your gauge and get it looked at within a few days.
How much does it cost to fix a P0116?
Repairs typically run $100 to $350. A sensor replacement is on the lower end, while a stuck thermostat or coolant system work raises the cost. The exact figure depends on which component is the real cause.
Is a P0116 code serious?
It's moderate. The repair is usually manageable, but inaccurate coolant readings can affect fuel mixture and overheating protection. Fixing it keeps your engine running at the right temperature.
Can a stuck thermostat cause a P0116?
Yes, that's one of the most common causes. A thermostat stuck open keeps the engine from warming up properly, so the coolant temperature never reaches the range the computer expects. Replacing the thermostat often clears the code in that situation.