Help with flickering lights and gearbox malfuction warning sign
 

Hi there, driving a 2009 B8 S5 with 104,000 km or 65,000 miles on it.
Stopped at a traffic light and noticed that lights on dashboard and mmi were flickering on and off with gearbox malfuction lights coming on and a beeping sound. Restarted the engine and pulled over. Gave it a 10 minutes break before attempting to switch it on again. Headlights were flickering and engine couldn start. Audio and aircon were working. Tried a few more times and only exception was that dashboard lights would sometimes be completely dead or came on for a second or so before dying off. The gearbox malfunction light only came on the first time round and even then, i could barely see it as the warning sign would completely die. Anybody else experienced problems similar to mine? Any input would be appreciated 😀

How old is your battery? Battery lead connections secure and firm without corrosion?

I would check your battery - other than that, you need to pull some codes. The other thing to check is that there is no water in any of the electrics - check the cubbies in the boot. I had something similar with the flickering and (different) fault messages and the codes described general communication errors. There was water in the roof motor. Cleaned the drains, dried the electrics, had a new motor fitted and the problem has not returned since.

Thanks for the advice. Had the car towed to a workshop but they couldn't find a problem with it. Car started well the following morning. The only thing pointed out was that the alternator overcharged. Car ran well for a week but same thing happened today while trying to start it up. Can anybody help please😓