OBD-II code · Network

U0605 Lost Communication With A/C Refrigerant Sensor A

The vehicle bus reports loss of communication with smart A/C refrigerant sensor A. Pressure or composition feedback for the refrigeration loop is unavailable; A/C may default to off.

Is it safe to drive with U0605?

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
0.5–2 h
Emissions test
Usually unaffected
After the fix
A drive cycle is needed before the light stays off
Parts involved
AC Refrigerant Sensor A, Vehicle Bus Wiring

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