Check Engine Code
P0117
Engine Coolant Temperature Sensor Circuit Low Input
What P0117 means
The ECT signal is at or near 5V, which the ECM interprets as extremely cold engine. Usually a wiring fault or a failed sensor.
Symptoms
- Check engine light
- Cold-start issues even when warm
- Rich running / black smoke
- Cooling fans running constantly
- Bad fuel economy
Likely causes (most common first)
- Damaged ECT sensor wiring (shorted)
- Failed ECT sensor
- Corroded connector
Can I keep driving?
Medium — drivable but fix soon
Typical repair cost
DIY fixes can start near $15 (parts only). Shop repairs for P0117 typically run up to $150 depending on the underlying cause and vehicle. Start with the most common cause — Damaged ECT sensor wiring (shorted) — before throwing parts at it.
Symptoms that match P0117
If you got here from a search query, one of these might describe what your car is actually doing:
Recommended parts & tools for P0117
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