Quote Originally Posted by RideMr2 View Post
I looked into this some more, I noticed something.

Whenever this buzz happens, something is pulling current.
My headlights dim for a second, after the buzzing stops, they brighten back up.

I was thinking this was tied to the tcs someway, guessing, as in that system is now online, it's now ready for use.
I don't know how to explain this though.

I used to see a message before I got new hubs put on;
It would say tcs active on the dic, then I would hear the buzzing noise.

After the hubs, I don't see the message tcs active, I only hear the buzzing noise.

I now realize this has something to do with the speed sensors coming online, being tested, not real sure how to explain it, since I don't really know what it's actually doing.

There is a very good chance that this is exactly what's going on with the OP's car.

OP, is your car an '04 and up? If yes, this is probably your answer. My 2005 does the exactly same thing as described above. Funny thing though, it didn't always do this.

This winter I had some bad wheel spin in a parking lot taking off on ice, so the TCS system was activating, then I braked and slide and the ABS activated as well, after sliding about 10-15 feet the ABS system shut itself down because it couldn't get the car back under contorl. The ABS light came on, then the TCS light as well. The HUD started popping up messages to check the ABS and TCS systems.

Once the car was shut down and re-started the lights stayed off, but every time I take off now the TCS system kicks in momentarily after first starting up. Sometimes the HUD will says "TCS active", other times it will not. It's random, but the constant to this is that the TCS system always buzzes after first taking off now.

I've had the battery unhooked several times since then for other tuning purposes, and it still buzzes on first takeoff now even after all settings being reset to stock. I should probably get under the car and check out the wheel sensors and clean them or replace them if needed...