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U02B7 Lost Communication With Rear Radar Module B

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U02B7 reports that rear radar B, the second corner unit at the back, has gone silent. Stellantis lists it together with U02B6 for the 2022-2023 Grand Cherokee and Wagoneer models in GPOP review 9100222 and relies on a side-to-side comparison: after a pin unlock the two rear corner radars are exchanged, so the fault either follows the sensor or stays on the harness side. A swapped or new radar must then be calibrated on a drive. Mercedes-Benz assigns rear radar B to the outer right position on the 2026 CLA electric, as its invalid-data code U05B855 shows. Since blind spot and cross traffic systems need both rear corners, a fault on one side usually disables the warning for that side, and some systems shut the whole function off.

Likely causes

Harness or connector on the side of radar B damaged or loose
Rear radar B failed
Radar replaced or swapped without completing the calibration drive

Symptoms

  • Blind spot lamp on one side stays off or shows a fault
  • Rear cross traffic alert unavailable

Repair estimate

DifficultyHardWorkshop job
Parts and labour€50–1,500
Time0.5–3 h

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

Parts involved

rear radar module bvehicle bus wiring

Related codes

U02B6U02B8U05B8U0233

References: static.nhtsa.gov, static.nhtsa.gov, en.wikipedia.org.