OBD-II code · Powertrain (generic)

P0117 Engine Coolant Temperature Sensor Low Input

The ECT signal voltage is below threshold, which the ECU interprets as an implausibly hot coolant temperature (typical NTC sensor characteristic — low resistance at high temperature).

Is it safe to drive with P0117?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelySignal wire shorted to ground
  • PossibleSensor failed shorted internally

Symptoms

  • Check engine light on
  • Cooling fan runs constantly or not at all
  • Cabin heater weak or excessively hot
  • Possible long warm-up time or hard cold start

Repair at a glance

Difficulty
Easy
DIY friendly
Often, with basic tools
Typical labour
0.3–1.5 h
Emissions test
Likely to fail
After the fix
A drive cycle is needed before the light stays off
Parts involved
Coolant Temperature Sensor, Coolant Temperature Sensor Wiring

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.