Error code

OBD2 P0117

OBD2P0117
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Engine Coolant Temperature Circuit Low.

Severity

moderateCan drive, but performance issues and potential overheating may occur.

Summary

P0117 indicates a low input from the Engine Coolant Temperature (ECT) sensor, suggesting that the sensor is reading an abnormally high engine temperature due to low resistance or voltage issues.

Symptoms

  • Check-engine light illuminates
  • Poor fuel economy
  • Engine may run rough or blow black smoke out the tailpipe
  • Poor idle, may start and then die

Common Causes

  • Defective ECT sensor
  • Short to ground on ECT signal circuit
  • Faulty or damaged connectors
  • Wiring harness damage or loose terminals at ECT or PCM
  • Overheated engine

Diagnosis

  1. Verify the actual coolant temperature using an infrared pyrometer or contact-type temperature probe.
  2. Check for damage or corrosion in ECT sensor wiring and connector.
  3. Test resistance of the ECT sensor while running the engine to ensure it matches manufacturer specifications.
  4. Inspect radiator cap, coolant mixture, and cooling fan operation.

Fixes

  • Replace defective ECT sensor

FAQ

What should I do if my check-engine light comes on with P0117?

Check the coolant temperature, inspect wiring and connectors for damage or corrosion, and test the ECT sensor's resistance. If issues persist, consult a professional technician.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

More OBD2 codes

All OBD2 codes →Search more codes →