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felixmystic5

Audi S8 Keyless Entry Trouble: Faulty Antenna Fix

Locking/Unlocking issue

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Ignition cannot be switched on

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Fault stored

Having issues with my 2008 Audi S8 keyless system. The central locking works intermittently, and I need to use the physical key to start the engine despite having keyless entry. The error memory shows related faults. After some research, I suspect the radio signal might be affected by a faulty bumper antenna. Has anyone dealt with similar symptoms on their S8? Looking for confirmation if the antenna mount or fm antenna could be the culprit, and what the repair process typically involves. Did you need a complete antenna repair or was it a simpler fix? Any feedback on repair costs would be helpful too.

4 comment(s)


patricia_bauer5

As someone with moderate experience working on Audis, I faced nearly identical issues with my 2006 Audi S6. The symptoms were exactly as you describe, intermittent central locking and keyless entry problems. After some diagnostic work, it turned out the automotive antenna connection in the front bumper was indeed the culprit. There was corrosion in the cable connector, causing poor signal transmission. The antenna repair involved replacing the damaged wiring and connector assembly, which cost 95 Euro including parts and labor. The fix was straightforward for a qualified technician, they replaced the vehicle antenna connector and verified all connections were properly sealed to prevent future corrosion. After the antenna replacement, the keyless system worked flawlessly again. Before jumping to conclusions though, could you share: Have you checked if the key fob battery is good? Are there any visible damages to the front bumper area? Does the issue occur more frequently in wet weather? Which specific error codes are you seeing? This information would help confirm if your issue matches what I experienced with the car antenna system.

felixmystic5 (Author)

Thanks for the helpful diagnosis details. Just had my 109081 KM service done last month, so I can confirm the key fob battery was checked and replaced then. The error codes point to signal interference in the front antenna circuit. Already checked the bumper area, there is minor scuffing near the automotive antenna mount, which might explain the connection issues. The problems definitely get worse in rainy weather, supporting the theory about water getting into a damaged fm antenna connection. Will book it in for antenna repair next week. The 95 Euro cost estimate sounds reasonable compared to what I was worried it might be. Hoping its just the connector like in your case rather than needing a full antenna replacement.

patricia_bauer5

Those symptoms combined with the weather sensitivity definitely match what I experienced with my S6. Since you mentioned the scuffing near the antenna mount, its almost certainly the same issue I dealt with. The antenna repair actually ended up being simpler than expected in my case. The technician found that water was seeping in through that scuffed area, causing signal interference with the car radio and keyless systems. They cleaned the corrosion, replaced the connector, and properly sealed the automotive antenna housing. One tip from my experience, make sure they thoroughly check all the antenna wiring while doing the repair. My first fix only lasted a few months because they missed some corroded wiring further along the cable run. The second repair included replacing the entire antenna cable assembly, which solved it permanently. Based on your mileage and the weather-related symptoms, I suspect youll need the complete antenna replacement rather than just the connector. While this might push the cost slightly higher than what I quoted, its worth doing the full job to prevent recurring issues.

felixmystic5 (Author)

Thanks for all the detailed input. After comparing notes with your experience, I'm convinced its the same antenna issue. The weather sensitivity and error codes are identical to what you described. The scuffing near my car antenna mount is pretty minor, but since water infiltration seems to be the common factor, I'll request they check the entire antenna cable run during the repair. Good tip about making sure they do a complete inspection, dont want to deal with the radio signal problems coming back in a few months. I'll budget for the full antenna replacement rather than just the connector fix, even if it costs a bit more than 95 Euro. With 109081 KM on the clock, makes sense to replace the whole vehicle antenna assembly while they're in there. Will update the forum once its fixed in case anyone else runs into similar keyless system problems.

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