Fuel & air metering · Powertrain · generic (SAE-defined)
P0116: Engine Coolant Temperature Circuit Range/Performance
P0116 means the engine coolant temperature (ECT) sensor is reporting values that do not make sense compared with how long the engine has run or with other temperature readings.
Standard title per SAE J2012 / ISO 15031-6 · Updated 2026-11-07 · By CarWhere Research
How P0116 sets
The powertrain control module (PCM) checks the ECT reading for plausibility. Typical tests include comparing it with intake air temperature after a cold soak, confirming the temperature rises at a reasonable rate after startup, and watching for readings that are stuck or jump. If the reading fails these checks, P0116 sets. The test methods vary by manufacturer.
Common causes of P0116
Roughly most likely first; the actual cause depends on the vehicle and needs testing to confirm.
- ECT sensor out of calibration
- Low coolant level or air pocket around the sensor
- Thermostat stuck open or opening early
- Intermittent wiring or connector fault
- Engine block heater use affecting cold-soak comparisons
- Wrong sensor installed
P0116 symptoms
- Check engine light on
- Inaccurate temperature gauge
- Poor fuel economy
- Hard starting or rough idle when cold
- Cooling fans operating at odd times
How P0116 is diagnosed
- Check coolant level and look for leaks or air in the system
- Scan for codes, including thermostat-related P0128
- After a cold soak, compare ECT with intake air and ambient temperature
- Watch ECT rise during warm-up and compare with an infrared thermometer
- Inspect connector and wiring
- Test sensor resistance against the factory chart
Typical fixes for P0116
- Replace the ECT sensor
- Top off and bleed the cooling system
- Replace a stuck-open thermostat
- Repair wiring or connector problems
Replace parts only after testing confirms the cause — a code names the circuit or condition that failed a check, not necessarily the faulty part. We don’t publish per-repair prices; for what households actually spend on upkeep, see car repair costs.
Related codes & warning lights
P0116 FAQ
What does code P0116 mean?
P0116 means the engine coolant temperature (ECT) sensor is reporting values that do not make sense compared with how long the engine has run or with other temperature readings. The standard definition is "Engine Coolant Temperature Circuit Range/Performance."
Can I drive with a P0116 code?
Usually yes for short trips, but monitor the temperature gauge and coolant level. If there is any sign of overheating, pull over and shut the engine off.
Can a thermostat cause P0116?
Yes. A thermostat that is stuck open can keep the engine from warming normally, which some PCMs flag as an implausible coolant temperature.
Can low coolant set P0116?
Yes. If the sensor is surrounded by air instead of coolant, its readings can be erratic or inaccurate.
Keep researching
Engine guides by brand (known issues, specs)
More fuel & air metering codes
Sources
- SAE J2012 — Diagnostic Trouble Code Definitions (standard code titles)
- ISO 15031-6 — Road vehicles: communication between vehicle and external equipment for emissions-related diagnostics, Part 6: Diagnostic trouble code definitions
- U.S. EPA — Vehicle Emissions Inspection and Maintenance (I/M) programs
- U.S. EPA, 40 CFR 86.1806-17 — Federal onboard diagnostics requirements for light-duty vehicles
- California Air Resources Board — On-Board Diagnostic (OBD) Program
General information written by CarWhere Research, not a diagnosis of your vehicle. Manufacturers can add their own sub-definitions and test conditions; confirm with the factory service information for your year, make and model. Before paying for a repair, check NHTSA for open recalls and your warranty booklet: federal law requires an emissions warranty on major emission-control parts such as the catalytic converter and engine computer.