abs and trac lock lights in dash come on. on 1999 Pontiac Montana

very eratic, when they come on if i shut engine off and restart the lights on dash stay off till next time which coulbe a day a week or whatever?? if they leave a code in computor should the deasler not be able to retrieve it??

Asked by for the 1999 Pontiac Montana
I have the same problem.
what I did was check the brake fluid level and it was low so I added some and the abs/trac light never came back on.