Mazda CX-5 Self Test Noise
 

Hi guys,
I’m wondering, have any of you noticed the various self-test noises from the vehicle’s systems right after you start driving? For example, the ABS self-check usually kicks in within the first few seconds of moving, typically around 5-10 mph (​​a few mechanical clicks from the front).

But there’s also another weird, one-time rough knock coming from the front end right after abs self-check. I’m pretty sure other CX-5 owners know what I’m talking about.
Just curious, which system could be doing a self-test that causes such a rough knock sound?
I tried googling it but couldn’t find anything useful.