P0116: Engine Coolant Temperature Sensor Circuit Range/Performance

What does P0116 mean?

Coolant temperature is not behaving as the computer expects. It may be an inaccurate sensor reading, a sticking thermostat, or another condition affecting warm-up rather than a completely open or shorted sensor circuit.

Generic OBD-II definition: Engine Coolant Temperature Sensor Circuit Range/Performance. Confirm applicability in your vehicle service information.

Common causes

• ECT sensor drift or poor connection
• Stuck-open or missing thermostat
• Signal or sensor-ground wiring fault

Symptoms

• Poor fuel economy
• Hard starting or rough idle
• Black smoke or stalling in some cases

Diagnostic focus

A plausible but unusually slow warm-up can point toward a thermostat. A sudden temperature jump points more toward the sensor or its wiring; use the trend to avoid replacing the wrong part.

Can I keep driving with P0116?

Severity: Medium Drive gently and get it diagnosed soon.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Check coolant level only when cold
• Compare cold-soak ECT with ambient and intake temperature
• Watch warm-up progression and test the thermostat and sensor as indicated

Sources & review

• OBD-Codes.com: P0116
• TroubleCodes.net: generic code definitions

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.