P0117 Ford Ranger
Engine Coolant Temperature Sensor Circuit Low · Powertrain Code · Medium · Repair: Easy
What is P0117?
The coolant temperature sensor is reading lower than expected — possible open circuit or faulty sensor.
When the Ford Ranger triggers code P0117 (engine coolant temperature sensor circuit low), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the Ford Ranger.
This repair is rated easy, meaning basic tools, no lift needed.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Ford Ranger.
Common Causes on Ford Ranger
- Failed engine coolant temperature (ECT) sensor — shorted internally
- Corroded ECT sensor connector due to coolant leak dripping on wiring
- Short to ground in ECT sensor wiring
- Damaged ECT sensor from coolant system overpressure
Symptoms
- Check engine light
- Electric cooling fans running at full speed constantly
- Gauge reads maximum temperature (or erratic)
- Rich running condition and poor fuel economy
- Hard starting in cold weather
Notes for Ford Ranger
On EcoBoost engines, a failing ECT sensor can cause the cooling fans to run on high constantly — easy to confirm with a scan tool reading coolant temp.