U05B8 code meaning
Invalid Data Received From Rear Radar Module B
What U05B8 means
Module B is the right-hand rear corner radar in the only public manufacturer use: Mercedes-Benz lists U05B855 for the outer right rear sensor of the 2026 CLA electric. The fault type 55 reads as not configured, so the content is rejected because the controller N62/5 has no valid setup for that sensor, not because the radar is broken. The May 2026 version of bulletin LI54.71-P-080345 narrows the case to cars built before 27 February 2026 with persistent warnings and drops the hardware reset step of version 1; afterwards the car must sleep for seven minutes, and full assistance returns after roughly ten more minutes of driving. Replacing the sensor is therefore rarely the first step. Right-side blind spot and cross traffic warnings fail. U02B7 means module B is silent.
U05B8 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U05B8
- Blind spot indicator on the right stays off
- Assistance warnings reappear on every start
- Rear cross traffic alert missing on the right
Common causes of U05B8
- Most likelyRight rear radar not configured, calibration of the assistance controller missing
- PossibleInitial calibration of the controller's acceleration sensor not completed
- Less likelyRight rear radar internally defective
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Rear radar module b
What each part of U05B8 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| B8 | The exact fault in that area. |
What to do next
- Note U05B8 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U05B8
What does U05B8 mean?
U05B8 means "Invalid Data Received From Rear Radar Module B". Module B is the right-hand rear corner radar in the only public manufacturer use: Mercedes-Benz lists U05B855 for the outer right rear sensor of the 2026 CLA electric. It is a generic code, so it means the same on every make.
Is it safe to drive with U05B8?
U05B8 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U05B8 fail an emissions test?
U05B8 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U05B8 to fix?
Difficulty: hard. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U05B8 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.