VSC and intermittent front brake drag

Hello,

2001 4Runner 4WD. I have had an intermittent sudden front left brake application on right curves, especially when the tire is low. The VSC light comes and beeps at the same time. Lately I have noticed the brake dust on the front left side is more predominant than the right, indicating drag. Now, the VSC TRAC and VSC Off lights are on along with the check engine light (oddly, the only codes are 401 and 402 related to emission control). So, when I clear the codes, the VSC light go off. Not sure if the caliper is dragging, or it is a VSC only issue, or, both.
Any hints?

UPDATE: I now know that when the Check Engine Light is on for whatever reason, the VSC is automatically disabled. The other issue is still current

 

Sounds like a bad caliper. Rebuild or replace.

 

Thanks, The caliper is only one issue that I know of. The intermittent sudden braking of the front brakes, I believe is related to the VSC, is what I don't have experience with.