CarSense › Trouble codes › P0116

P0116: Engine Coolant Temperature Circuit Range/Performance Problem

What this check-engine code means in plain English, what usually causes it, and what a fix typically costs.

Severity: Monitor — not an emergency, but address promptly

What P0116 means

The engine control module (ECM) has detected that the engine coolant temperature (ECT) sensor signal is not changing at the expected rate or is outside the normal operating range. This means the sensor readings don't match what the computer expects based on engine runtime, ambient temperature, and other inputs.

What causes P0116?

Likely
Faulty coolant temperature sensorThe ECT sensor itself has failed or is providing erratic readings due to internal degradation.
Likely
Stuck-open thermostatA thermostat that stays open prevents the engine from reaching proper operating temperature, causing abnormal sensor readings.
Possible
Low coolant levelInsufficient coolant can cause inaccurate temperature readings and prevent proper engine warm-up.
Possible
Wiring or connector issuesCorroded connectors or damaged wiring between the ECT sensor and ECM can cause intermittent or incorrect signals.

Is P0116 safe to drive?

Drive it?
Usually yes, short-term
Watch for
Overheating, poor fuel economy, rough idle when cold
DIY-friendly?
Sensor replacement is moderate DIY; thermostat requires coolant drain

You can typically drive short distances, but the engine may run rich (wasting fuel), have poor heater performance, or take longer to warm up. If the temperature gauge shows overheating or the engine runs extremely hot or cold, stop driving immediately as this can cause serious engine damage.

P0116 repair cost

~$100 – $300+

Industry-average estimates. Cost depends on whether you need just the sensor, the thermostat, or both, plus labor for coolant system work.

Which one is it for your car?

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