U02B9 Lost Communication With Rear Radar Module D

Rear radar module D completes a set of four rear sensors, a layout that only a few vehicles with extended rear sensing use. No manufacturer documents U02B9 publicly; there is no published fitting position, timeout or lamp rating. The code states that module D no longer responds on the bus. As with its siblings, the cause lies in wiring, connector or supply more often than in the radar itself, and Bosch radar systems show why one silent unit rarely blinds the car completely: rear warnings such as cross traffic alert draw on several sensors, so the assistance controller withdraws only the affected functions or reports limited availability. The engine lamp stays off, and driving itself is unaffected.

Likely causes

Symptoms

• Some rear assistance functions unavailable
• Message about limited driver assistance

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: bosch-mobility.com, bosch-mobility.com.