P0116 code meaning
Engine Coolant Temperature Sensor 1 Circuit Range/Performance
Powertrain system Generic code P01xx codes Check engine light
What P0116 means
The engine coolant temperature sensor 1 is an NTC thermistor: the control module feeds 5 V through a resistor, and as the coolant warms the resistance and signal voltage fall. Its value drives cold-start enrichment, idle speed, ignition timing, the radiator fan and the release of closed-loop mixture control. Some Ford engines measure cylinder head temperature instead and calculate a coolant value from it. P0116 is a plausibility fault: the signal is electrically valid but not believable. Most often it checks for a sensor stuck too warm. After a long soak (GM 8 h, Ford 6 h) coolant must be close to intake air temperature; GM fails it above about 19 °C difference without a detected block heater, Ford if it reads over 110 °C or sits at 79–110 °C. Ford diesels instead check whether coolant warms fast enough in frost. A sensor stuck warm suppresses cold-start enrichment and can defeat the thermostat monitor, which is why CARB requires this test. GM uses one or two trips depending on the engine.
P0116 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0116
- Check engine light on
- Poor cold start (too little enrichment)
- Higher consumption or idle problems
- Often no noticeable symptoms
Common causes of P0116
- Most likelySensor drifting and reading too warm (ageing, coolant ingress)
- PossibleCorrosion or contact resistance in connector or wiring
- PossibleBlock heater or preheater not detected
- Less likelyComparison sensor (intake air, ambient) wrong
- Less likelyControl module calibration
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Engine coolant temperature sensorEngine coolant temperature sensor wiring
What each part of P0116 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1 | Area: fuel and air metering. |
| 16 | The exact fault in that area. |
What to do next
- Note P0116 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0116
What does P0116 mean?
P0116 means "Engine Coolant Temperature Sensor 1 Circuit Range/Performance". The engine coolant temperature sensor 1 is an NTC thermistor: the control module feeds 5 V through a resistor, and as the coolant warms the resistance and signal voltage fall. It is a generic code, so it means the same on every make.
Is it safe to drive with P0116?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0116 fail an emissions test?
Yes, it can. P0116 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0116 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0116 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.