this maybe the switch dont know were it it on the s80 but the s40 is under the left wing i found it can be ajusted pull the cap off it and there is a hex key hole in the top try turning it till it stops and found that the pumps get a lot of dust in them fixed my old pump well just needed a clean out and im know selling it on ebay

 

hey tech, where is that valve located? Do you knoiw the part# by any chance? thanks!

 

...the fog lights. i had them disconnected and buzzing stopped. now the ac is freezing up, so will search for that link!

 

I have had my car (2002 S80) for 2 years and it has always done that. I thought it was just normal. You shut off the car and every once in a while you hear a buzz noise for about 5 to 10 seconds. And it does that for a few minutes after it has been shut off. I have not timed how long it is on or for how long it does it. I just figured it was normal. Everything else seems to be working fine, although my ABS module appears to be bad based on the symptoms, codes etc, but now I am wondering if this is a possible culprit instead of the module itself.

 

...a/c? and strut mounts?

 

Just try replacing the vacum brake pump . They often go bad on these vehicles . It's about $120 on ebay and it will take you no more than 5 min to replace it . See if that will help

 

I had this happen to me a while back. As I investigated I literally saw something from the right side of the engine shoot off into oblivion and never found the piece. Turns out, the vacuum switch (P/N W0133-1971446 depending on your model) is two pieces, and includes an internal spring and a diaphragm. The plastic became brittle and caused both a vacuum leak and then the spring shot the top of the switch off of the car when I touched it.

The behavior of the switch was such that the vacuum pump ran continuously when the switch was in the failed state. Worth a look, unfortunately the switches aren't cheap at about 70 bucks.

 

Hello! Could you please let me know if you made any progress on this? let me know if you got an answer on this!!

 

I have the same issues. says key is still in when I take it out. Makes that buzzing sound, but not all the time just randomly.. and it must put my car in emergency shut off or something because I have to disconnect the negative battery terminal to get the car started! Please let me know if anyone found anything else out. Thanks.

 

even after I take key out it dings like the key is still in. Makes this weird buzzing noise after the car is off and I have to disconnect the negative battery terminal. Today my car won’t start at all. Please help!

 

so I think I figured out what the noise is.. it’s the parking brake.., not sure why it does it or also only why it does it randomly and not all the time!! I figured it out by pushing on the brake and pulling on the parking brake lever. Hope that helps you!