Help Me!

there is a bar in the rear of the vehicle, it is right before the gas tank skid plate. it goes from the axle to another device. recently i let an idiot friend tow another vehicle and he attached the straps to it. well now it is bent and a check engine light is on. repair shop told me it was \"rough road sensor\", obviously they didnt check to thoughouly or they would have noticed the bent bar. i would like to know what this bar is and how much its going to cost me for a new one. (so i can do it without parents knowing) THX!!:(

it would be helpful to know what year model it is. it may only be a stablizer bar.