Startup BIOS communicates POST errors as a series of beeps before it tests video. Search the web site of the motherboard or BIOS manufacturer to know how to interpret a series of beep codes.
it is your air bag control module it beeps in a series of 5 beeps to indicate thet there is a malfunction
It issues a number of short beeps.
Through a series of audio beeps, different numbers of beeps mean different errors depending on your bios manufacturer.
issues a number of short and long beeps
By using a code of short and long beeps
POST will indicate error messages by a series of beeps or a series of lighted-up LEDs (depending on your computer).
When it starts up a Mac runs tests to check the hardware. It beeps to indicate where a problem may occur. 3 beeps indicates a problem with the memory. It is usually advisable to have an Apple service shop have a look at any Mac that is beeping at startup.
Beeps at start up indicate that something is wrong. Often it is a bad memory module, possibly not pushed in tight enough to form a solid connection. (See links below)
there is a keyboard error.
Before anything, ask your computer's manufacturer. The second thing you should do is listen for beeps. If you hear multiple beeps on startup, look up the manufacturer of your motherboard, and find the beep code section. That may tell you what's wrong. Google for a fix. If there are no beeps, but you have heard them before, something either came unplugged, or fried. Talk to your manufacturer. If there never were any beeps, you should talk to your manufacturer before ever opening the case, which most likely will be necessary.
If Your BMW 525I backup sensor still beeps even when the car is in drive, it could be a faulty fuse. It could also indicate a wiring problem.