How much does it cost to fix P0116?

DIY repair typically costs $10–$50 for parts. Professional repair runs $150–$400 including parts and labor.

P0116

Powertrain

Moderate

Engine Coolant Temperature Circuit Range/Performance

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The P0116 code means your engine's coolant temperature sensor is sending readings that don't match what the Engine Control Module (ECM) expects based on driving conditions. Rather than a simple open or short circuit, this code flags a performance issue — the sensor is responding, but its readings are outside the normal range for how long the engine has been running or the conditions it's operating in.

This is most commonly caused by a stuck thermostat. When the thermostat sticks open, the engine never fully warms up, and the ECM notices the coolant temperature isn't rising as it should. A failing ECT sensor or low coolant level can also trigger this code. In some cases, air pockets trapped in the cooling system after a coolant service prevent the sensor from getting accurate readings.

While this code won't leave you stranded, it should be addressed within a week. The ECM uses coolant temperature data to control fuel mixture, ignition timing, and transmission shift points. Incorrect readings mean your engine may run rich, waste fuel, and produce higher emissions. If the thermostat is stuck, your heater may also blow cold air in winter. Start by checking your coolant level and thermostat operation — a thermostat replacement is an affordable fix that resolves the majority of P0116 cases.

Severity

Moderate — Address SoonThis Week

Symptoms

•Check Engine Light illuminated
•Engine takes unusually long to warm up or overheats quickly
•Poor fuel economy and rough running when cold
•Temperature gauge reads erratically or stays at one extreme
•Heater blows lukewarm or cold air

Likely Causes

Stuck or failing thermostat35%

A thermostat that is stuck open or partially open prevents the engine from reaching proper operating temperature, causing the ECT reading to stay out of the expected range over time.

Faulty Engine Coolant Temperature (ECT) sensor30%

The ECT sensor's internal thermistor can degrade with age, providing readings that don't match actual coolant temperature and falling outside the ECM's expected performance range.

Low coolant level or air pockets in the cooling system20%

Insufficient coolant or trapped air around the ECT sensor causes inaccurate temperature readings because the sensor isn't fully submerged in coolant.

Corroded or damaged wiring/connector at ECT sensor15%

Corrosion or loose connections in the ECT circuit create resistance changes that alter the voltage signal, producing readings outside normal parameters.