Here is the origin of the problem:

One day I replaced both rear calipers, rear disks, and rear pads. I bled the brakes and the person I was working with let go some ABS brake fluid by bleeding the ABS system as well (I don't think he knew what he was doing. I think all he did was he opened the valve once and closed it but some brake liquid did come off). It's now been about 6 months and the abs unit always make a zzzzzzzzzzzzzzz noise when I start the car. It's driving me crazy!!!!! Plus, it seems to be longer and longer. Now, I would say it takes about 35 seconds for the noise to stop and the ABS light to go on.

Thanks for the DTC 1 description, I will check if I have ABS brake fluid leakage tonight. If not, I will make sure I have enough ABS brake fluid (dot3) in the ABS reservoir, will bleed the ABS system, and fill up the ABS reservoir. I hope this will do it.