What usually causes it
- A failed coolant temperature sensor
- A broken wire or a loose, rusty plug
- Low coolant, so the sensor cannot read the true temperature
- A fault in the engine computer, which is not common
P0118Starts at: Get it checked this week
Coolant temperature sensor signal is too high
The coolant temperature sensor tells the computer how hot the engine is. Its signal is high, so the computer may think the engine is colder than it is and use the wrong fuel mix and fan settings.
Check this first
Only when the engine is fully cool, look at the coolant level in the plastic tank. Never open the radiator cap on a hot engine.
What to watch for
- The temperature gauge stuck on cold, or climbing into the hot zone
- Cooling fans not coming on
- Black smoke, poor gas mileage or hard starting
Can I keep driving?
We rate P0118 as Get it checked this week. It is not an emergency yet, but it can get worse. If the light starts flashing, stop driving soon.
Quick answers about P0118
What does P0118 mean?
Coolant temperature sensor signal is too high. The coolant temperature sensor tells the computer how hot the engine is. Its signal is high, so the computer may think the engine is colder than it is and use the wrong fuel mix and fan settings.
Can I keep driving with P0118?
We rate P0118 as Get it checked this week. It is not an emergency yet, but it can get worse. If the light starts flashing, stop driving soon.
What usually causes P0118?
The most common causes, in order: A failed coolant temperature sensor; A broken wire or a loose, rusty plug; Low coolant, so the sensor cannot read the true temperature; A fault in the engine computer, which is not common.
Estimates only. A mechanic should confirm. The same code can mean slightly different things on different cars; the app explains it for your exact year, make, model and mileage.