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!

Network generic / SAE

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.

SystemNetwork
Typegeneric / SAE
GroupU0
Range / number4 / 06

Possible causes

  • Radar obstructed by snow/dirt high
  • Radar misaligned after collision medium
  • Gateway module routing CAN messages incorrectly low

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

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 80–1500 €
  • Estimated time: 0.5–3 h
  • Component: acc radar
  • MIL / check engine light

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