P0117 Code: Engine Coolant Temperature Circuit Low Input
🟠 Moderate severity · drivable
Drivable, but the computer may think the engine is hotter than it is, causing poor warm-up running.
What P0117 means
The engine coolant temperature (ECT) sensor is reading very hot (low voltage), usually because the circuit is shorted or the sensor is faulty. The computer may think the engine is overheating when it isn't.
Symptoms
- Check engine light is on
- Cooling fans may run constantly
- Poor fuel economy
- Temperature gauge reading wrong
Common causes
- most common: Faulty engine coolant temperature sensor (shorted)
- common: Shorted wiring in the ECT circuit
- less common: Corroded sensor connector
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Replace the engine coolant temperature sensor | Yes | $30–100 |
| Repair shorted ECT wiring | Mechanic | $50–150 |
Frequently asked questions
Can I drive with a P0117 code?
Yes, but the computer's wrong reading can hurt warm-up running and fuel economy. Fix it soon.
What is the most common cause of P0117?
A faulty coolant temperature sensor that has internally shorted.
How much does it cost to fix a P0117?
Typically $30–$100 for a new coolant temperature sensor.
Related codes
P0116
P0116 Code: Engine Coolant Temperature Sensor Range/Performance
P0118P0118 Code: Engine Coolant Temperature Circuit High Input
P0115P0115 Code: Engine Coolant Temperature Circuit Malfunction
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.