It just means you won't have ABS anymore. The brake should work fine though. Unless there's a way that I haven't heard about (with magic touches and whatnot) to clearing the light, the only way to clear that code and that light is to hook your truck up to a scan tool and clear it that way. It's not like a Check Engine light where you just unplug the battery or pull the ECM fuse for a minute or two. And if there's an actual problem and that's a current code, well, that's a whole nother story, and you'll probably have to get that fixed.