P0117 Nissan Altima
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 Nissan Altima 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 Nissan Altima.
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 Nissan Altima.
Common Causes on Nissan Altima
- Failed engine coolant temperature (ECT) sensor
- Short circuit in ECT sensor wiring
- Corroded ECT sensor connector
- Coolant system issue causing actual overcooling
Symptoms
- Check Engine Light on
- Radiator fans running at full speed constantly
- Temperature gauge reads cold
- Rich fuel mixture and poor economy
Notes for Nissan Altima
The ECT sensor on Nissan engines is inexpensive; replace it as a first step rather than extensive wiring diagnosis.