OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

P0116

Engine Coolant Temperature Sensor Range/Performance

The coolant temperature sensor reading does not change plausibly during warm-up, or its value disagrees with the intake air temperature when the engine has been off long enough that they should match. Often caused by a sensor that reports near a fixed value despite engine warm-up.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 16

Possible causes

  • Sensor drifting outside specification high
  • Thermostat stuck open (engine never reaches operating temperature) medium
  • Sensor element aged beyond calibration window low

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

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 30–250 €
  • Estimated time: 0.3–2 h
  • Component: coolant temperature sensor
  • Component: thermostat
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication