What is under a car bumper?
A bumper is more than its painted cover. Behind it sit a part built to crush, called the energy absorber, and a strong reinforcement bar that spreads a hit, and on some cars there are crush boxes and sensors too.
What are the parts, from the outside in?
This is the typical order. Parts vary by vehicle, and not every car has every part.
1. Bumper cover. The painted outer skin you see.
2. Energy absorber. A crushable part behind the cover that soaks up a small hit. I-CAR says it is "designed to absorb minor collision energy by crushing or collapsing" and is typically built for one-time use, so it is replaced if it is damaged.
3. Reinforcement bar. A strong bar that spreads a hit across the car. I-CAR says it is made from very strong materials, such as ultra-high-strength steel or aluminum, and its job is "to distribute the collision energy." It is replaced if damaged.
4. Crush boxes. Some cars have small parts between the reinforcement and the frame. I-CAR says they are "designed to be sacrificial parts," are replaced if damaged and are not straightened. Some reinforcements have them built in.
5. Mounting points. Where the bar attaches to the car. I-CAR says to inspect them.
6. Sensors and wiring. Radar, camera and ultrasonic sensors can be in or behind the cover.
I-CAR's page lists these parts but does not state their placement, so the order above is a typical sequence.
Can sensors be behind a bumper?
Yes, on some cars. AAA says radar, camera and ultrasonic sensors may be "located in or behind the front and rear bumpers," and that even minor incidents can damage this technology. AAA also says that after a sensor is replaced, the system "must be calibrated, which requires special training, tools and information." Calibration means setting a sensor so it reads correctly again. See also our guide on why a windshield or bumper repair can need a sensor check.
Do automakers limit repairs?
Some do. I-CAR quotes Honda/Acura barring repair of cover areas over or near radar units, and several makers saying a damaged reinforcement must be replaced, not straightened. These are statements by some makers, not rules for every car.
What can I ask?
Which parts behind the cover were looked at? Does my car have sensors in or behind the bumper? Does the maker's repair information say anything about repairing or replacing these parts on my model?
General information only. This page does not say what any iDeal shop offers. Naming a source does not mean any iDeal shop is certified by it or affiliated with it.
Request a repair estimate
Tell us what happened and where the damage is. A person at iDeal Automotive Group will try to reach you and connect you with one of our body shops.
Have a question about your bumper? Tell us what happened.
Use the estimate form Calls to this number are answered by iDeal Automotive Group, who connect you to one of our body shops. Ask for a specific shop if you have one.(917) 672-3726Read next
How is paint matched to my car?Matching paint takes more than a color code.
What is the difference between OEM, aftermarket and used auto parts?OEM parts are made by the car's original manufacturer, aftermarket parts are made by another company to work like the original, and used (recycled) parts were on another vehicle and then removed and resold.
What is the difference between paintless dent repair and body filler?Paintless dent repair removes a dent by pushing or pulling the metal without damaging the finish, and it needs access to the back of the panel without cutting holes.