OBD-II code · Powertrain (generic)

P01E4 Engine Coolant Temperature Sensor 3 Circuit Range/Performance

ECT sensor 3 reading implausible. The engine coolant temperature sensor feeds warm-up enrichment, fan control and closed-loop entry — a stuck-cold reading keeps the engine in open loop and rich forever.

Is it safe to drive with P01E4?

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

Common causes

  • Most likelySensor reading drifted
  • Less likelySensor element aged beyond calibration window
  • Less likelySensor mounting loose - signal damping

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
Ect Sensor 3

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