Intresting Issue

[Dachristianman]

So my new-to-me '03 Q45 has an interesting issue and maybe you all can help me narrow down my search. When I start the car, I put it in drive and idle away from wherever I'm parked, but as soon as I touch the accelarator, something under the hood makes an interesting noise. The noise only happens for less than a second and sounds like a brief grinding or what I would describe as a noisy AC compressor engaging. I've narrowed it down to being associated with pushing the accelarator pedal, but I'm not sure what it would be, and it only happens once during the drive. If I turn the car off and start it again, it does it once more, but only once per starting of the engine. I've turned off the A/C and the VDC it still makes the noise.

I'm guessing these cars are drive-by-wire and there is something under the hood associated with that system that is making a noise, but maybe someone can confirm.

Tom

[Q451990]

It sounds like the ABS self-test to me. The noise is more pronounced in colder weather.

Heath

[Skibane]

It sounds like the ABS self-test to me. The noise is more pronounced in colder weather.

That's an excellent call.

The ol' ABS "grunk" - My '12 Frontier has it in spades...

[Dachristianman]

Thanks guys. So this morning, I let the car idle forward in drive without touching the accelarator, and even shifted it up into neutral and hit the accelarator and it didn't make the noise. I shifted back into drive and let the car accelarate on it's own and at about 5-7 mph, it make the noise. Sounds like Bruuunnnkkk. <-- Say that slowly and you'll hear the sound. Does that still line up with your diagnosis of it being the ABS self-test and should I worry about it? It's loud enough to turn heads every now and then.

Tom

[Skibane]

The self-test typically occurs at a little faster speed than 5-7 MPH (more like 12 MPH or so), but it varies with year and model. So - Yeh, that sounds like it.

The ABS self-test is a normal thing - definitely not something to worry about.