Hi all....I took delivery of a '11 RDX AWD about a month ago. I have noticed that the vehicle often makes a short grinding noise a few seconds after driving, but it only seems to do it after it's been sitting for awhile. The timing and duration of the noise is comparable to when a vehicle is configured to lock the doors after take-off, but that's definitely not what is happening with my RDX as I have that feature turned off.

Sometimes, when the noise occurs, I can feel something in the brake pedal.

I'm inclined to take it back to the dealership, but I thought I would check here first to see if this is normal or a known problem. I checked past threads, but didn't see anything on point (unless I just missed it).

Thanks!

 

That sounds like the VSA Modulator Control Unit automated test, which occurs at 10 mph after each time the RDX is started. The VSA and ABS pump is operated briefly and brake lines to the master cylinder are pressurized, causing some light kickback in the brake pedal -- felt if you happen to be resting or pressing on it.

The pump may be more noticable after the car has sat for a while, because the system and fluid is cold. It's also possible that the test applies lght pressure to the pads, which are scraping on light surface rust accumulated on the rotors after the car has gotten wet.

It's a normal test, but just the same, you should take it in and have them check the brake diagnostics on the HDS computer hook-up.

 

See also: https://acurazine.com/forums/1g-rdx-problems-fixes-160/squeezing-squealing-noise-startup-813245/