OBD-II code · Network

U063F Lost Communication With Engine Coolant Flow Control Valve Position Sensor

The vehicle bus reports loss of communication with smart engine coolant flow control valve position sensor. Closed-loop control of the flow valve loses its actual feedback.

Is it safe to drive with U063F?

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

Common causes

  • Most likelyBus wiring open or shorted
  • PossibleModule without power or ground
  • PossibleModule failed

Symptoms

  • Multiple warning lights may illuminate
  • Affected modules may go into limp mode or shut down
  • Specific functions inoperative depending on module
  • Diagnostic tools may show communication faults

Repair at a glance

Difficulty
Medium
DIY friendly
Best left to a mechanic
Typical labour
0.5–3 h
Emissions test
Usually unaffected
After the fix
A drive cycle is needed before the light stays off
Parts involved
Coolant Flow Valve Position Sensor, Vehicle Bus Wiring

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