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noahblaze1

Q8 Sensor Failures Disrupt Multiple Safety Systems

Warning light in the speedometer of the vehicle

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Failure of various systems in the vehicle

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Error message in the speedometer

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Fault stored

My 2020 Q8 is acting up with multiple system failures and warning lights on the dash. The adaptive cruise control is completely dead. Seems like the radar sensor might be the culprit since collision avoidance and other electronic systems are failing too. Had a bad experience with my usual mechanic last time, so looking for recommendations on where to get this diagnosed properly. Car has 84114km on the clock and runs on gas. Anyone dealt with similar issues? What was the fix and rough cost estimate?

4 comment(s)


lukaseagle26

Had the same radar sensor issue on my 2017 Q7 3.0 TFSI last winter. The adaptive cruise control completely shut down along with forward collision warning systems. Multiple electronic failures appeared simultaneously on the dashboard. The root cause was a misaligned front radar sensor after a minor impact with road debris. The sensor malfunction triggered a cascade of electronic issues since modern safety systems are interconnected. The radar calibration had to be performed using specialized diagnostic equipment. The repair process involved: Full diagnostic scan, Physical inspection of the front radar sensor, Cleaning and realignment of the sensor, Complete radar calibration, System reset This was not a particularly serious issue, but required specific expertise and equipment to resolve. Regular workshops often lack the proper tools for radar calibration, which is why they might struggle with these electronic issues. The repair took about 4 hours total. Now all systems function normally, including adaptive cruise and collision avoidance. Would strongly recommend going to a certified dealer for this type of electronic diagnosis rather than a general mechanic.

noahblaze1 (Author)

Thanks for sharing your experience with the radar sensor repair. My Q8 had very similar symptoms with the adaptive cruise and safety systems failing. Mine turned out to be electrical interference from a faulty wiring harness rather than sensor misalignment, but the diagnostic process was similar. Would be curious to know what the final cost was for your repair since these automotive sensor issues can vary quite a bit in price. Has everything stayed working properly since the calibration or have you noticed any other electronic issues popping up? Sometimes these sensor malfunctions can be early warning signs of other problems.

lukaseagle26

After getting the sensor malfunction checked out at the shop, I can confirm it was actually just a dirty sensor causing all those system failures. The total bill came to only 45 Euro for cleaning and checking the radar sensor alignment. Much simpler fix than my initial concerns about calibration and wiring. Since the cleaning, the adaptive cruise and collision avoidance systems have worked flawlessly for the past few months. No sensor failure warnings or electronic issues have returned. The front radar is now functioning exactly as it should. This experience taught me that even minor debris or dirt buildup on these sensitive components can trigger multiple system warnings. Regular sensor cleaning during maintenance might help prevent similar issues. Definitely less stressful than dealing with more complex electrical problems like your wiring harness situation.

noahblaze1 (Author)

Just got back from the shop today and wanted to close the loop on my Q8 sensor issues. Turned out the wiring harness replacement and recalibration of the radar sensor cost me 890 Euro total. More than I hoped but less than I feared. The technician found corrosion in the main wiring connector feeding the front radar sensor, which explained all those system failures. They had to remove the front bumper to access everything properly. The automotive sensors are pretty sensitive to any electrical issues, so the damaged wiring was causing all sorts of chaos with the collision avoidance systems. The repair took about 6 hours including the radar calibration process. All warning lights are now off and the adaptive cruise works perfectly again. Going to a specialized shop definitely made a difference, they knew exactly what they were looking for and had all the right diagnostic equipment. Would rather have had your simple cleaning fix, but at least its properly sorted now. Thanks everyone for the input, really helped me understand what I was dealing with.

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