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.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
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
Common causes
Ordered by how often each turns out to be the cause.
- Radar obstructed by snow/dirtCommon
- Radar misaligned after collisionPossible
- Gateway module routing CAN messages incorrectlyLess likely
Parts involved
- Acc Radar
U0406 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.