Before you buy: How to find out if a used car has an unrepaired safety recall

About 5 million used cars under recall were sold last year before the recalled parts were fixed.

A study by Carfax, which sells vehicle history reports, showed that overall there are more than 46 million cars and trucks on U.S. roads with unrepaired safety recalls.

Some of the recalls were for serious safety problems, like leaky brake lines or air bags that can inflate with too much force, sending shrapnel into drivers or passengers. But others are relatively minor, such as brake master cylinder caps with pictures rather than words.

No matter the problem, if you're shopping for a used car, you want to make sure recall repairs have been done. Here's how to protect yourself:

FIND OUT IF THERE'S A RECALL: Get the 17-digit vehicle identification number from the seller, or copy it down from the left side of the dashboard near the windshield. Go to the National Highway Traffic Safety Administration's VIN lookup site at https://vinrcl.safercar.gov/vin/ and key in the number. The site will tell you if there are any open recalls.

GET A VEHICLE HISTORY REPORT: You can pay a third party such as Carfax or Experian's AutoCheck for a vehicle history check. It will show the car's ownership history, if it's been in a crash, and if there are open recalls. Complete reports cost around $20 to $40 for a single vehicle. www.autocheck.com and www.carfax.com

ASK THE DEALER: Many dealers will check used cars for open recalls. Ask them to do it while you're watching. Many have policies of repairing recalls before selling cars, and others will give you a vehicle history report at no charge.

CONSIDER A CERTIFIED PRE-OWNED VEHICLE: Manufacturers' certified pre-owned cars often cost more, but all major manufacturers say they check for recalls and fix the cars before selling them.