P0116 - Engine Coolant Temperature Circuit Range/Performance

The coolant temperature sensor signal is outside the expected operating range.

Treat the code as the starting point: compare symptoms, likely causes, and repair paths before pricing parts or moving into an estimate.

Code Overview

The coolant temperature sensor signal is outside the expected operating range.

Common Causes

• Coolant temperature sensor reading skewed
• Thermostat stuck open or not regulating correctly
• Low coolant level or trapped air in the system
• Wiring or connector issue at the ECT sensor

Symptoms

• Temperature reading does not match actual warm-up behavior
• Poor fuel economy during warm-up
• Cooling fan or temperature-gauge behavior may seem off

Diagnostic Steps

1. Compare ECT to ambient temperature on a cold start
2. Inspect coolant level and make sure the system is full with no trapped air
3. Review warm-up behavior to see whether the thermostat is regulating correctly
4. Inspect the ECT connector and wiring before replacing parts

Repair Difficulty

Moderate

General difficulty estimate for the most common repair path.

Likely Repairs & Cost Guides

Use symptoms, scan data, and quick checks to confirm the likely repair path before pricing parts. The estimator helps compare repair paths before replacing anything unnecessarily.

Related OBD Codes

Browse nearby code-family pages when the same fault pattern overlaps across systems, such as misfire, lean fuel trim, EVAP sealing, cooling, or charging faults.

Next Steps

Move from code lookup to diagnosis, then estimate the likely repair only after symptoms, causes, and checks point to the same path.