OBD-II code · Network

U0406 Invalid Data Received from Cruise Control Front Distance Range Sensor

ACC receives bus messages from the radar but their content is implausible (e.g. negative distances, jittering targets). Adaptive cruise is disabled until the radar reports plausible data again.

Is it safe to drive with U0406?

Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.

Common causes

  • Most likelyRadar obstructed by snow/dirt
  • PossibleRadar misaligned after collision
  • Less likelyGateway module routing CAN messages incorrectly

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
Hard
DIY friendly
Best left to a mechanic
Typical labour
0.5–3 h
Emissions test
Usually unaffected
Parts involved
Acc Radar

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