Bumper Repair: FAQ

Education posted on 12/12/18

The typical vehicle bumper is constructed to reduce damage to the front and rear ends of vehicles during low speed collisions. Bumpers are not typically designed to be structural factors that would protect occupants during any type of front or rear collisions. They are usually designed to protect the hood, grille, and cooling system at the front of the vehicle while the trunk, fuel and the exhaust system at the rear of the vehicle are somewhat protected during low speed collisions.

Prior to disassembling a bumper for repair, it’s important for any technician to do a complete diagnostic scan. An asTech® Remote Diagnostic Device will determine exactly where the damaged parts are located. This scan will help the technician know exactly which parts are needed before repairs are started.


Removing and installing a damaged bumper, whether to repair or to replace entirely, is no longer straightforward as loosening a few bolts.Modern bumpers are connected to numerous vehicle systems, which involves taking added time to disconnect these systems from the bumper prior to disassemble.

Repairing When Electronics Are Involved

Bumper systems have become quite complex over the years. These are some of the systems that are built into the bumpers:

  • Lights: including turn signals and fog lights can all be hardwired into a bumper. These lights must all be disconnected and removed before being replaced or reinstalled.
  • Blind Spot Monitoring Systems: Even a misaligned radar sensor as a result of vehicle damage can result in the MSM System not operating correctly.
  • Park Assist Systems: Any misaligned bumper can stop the park assist from operating effectively and turns itself off.
  • Trim: The bumper from modern vehicles usually has several trim pieces which need to be carefully removed prior to the repair or replacement process.
  • Warning Systems: Back up sensors, back up cameras, vehicle sensors, lane-change warning sensors, and more in a modern vehicle bumper.
  • Airbag Sensors: Many bumpers contain sensors which are need for airbag deployment.

When parts have to be replaced, always ensure OEM parts are used. Using other replacement parts may weaken the system. If another collision were to happen in the same area of the vehicle, it could cause more damage than if OEM parts were used.


Using the asTech® Remote Diagnostic Device, you can identify the trouble code from each of the systems and allow technicians to correct any problems. Blind spot Monitoring Systems, Lane Departure Warning Systems, Parking Assist Systems and Adaptive Cruise Control can all be defective after a crash involving the bumper. Most sensors can’t be repaired. If it’s been damaged, it needs to be replaced.

All sensors must be safely removed before the repair or replacement process begins. Any sensor that may have withstood physical damage from the result of a collision or other damage should automatically be replaced, even if their appearance doesn’t seem to warrant replacement. Also, any time a bumper cover has to be removed, the sensors must all be recalibrated once replaced.

Because crash sensors are sealed units, they cannot always be determined of their true condition just by their appearance. Most crash sensors are designed to be electronically opened as long as they are in their rest condition. One check which can be performed is to check for continuity with an ohmmeter. If the sensor contacts have remained closed, the sensor has not reset itself and should be replaced.

The air bag control module automatically self-checks each crash sensor every time the engine is started. If the air bag warning light is not on, the sensors assume that sensor to be fine. If a fault is detected during the diagnostic scan, the air bag warning light will come on and usually deactivate the air bag system.

Post Scans

Once all of the parts have been disassembled, repaired or replaced and ready to be reassembled, it’s important to do another diagnostic scan with the asTech® Remote Diagnostic Device. This will determine if the damaged parts have all be identified and replaced before everything gets put back together. If the bumper and its parts are reassembled before another scan with the asTech® Remote Diagnostic Device, there may be other issues that have to be dealt with. The disassembling of the bumper again to replace or repair any other issues will add time and cost to the repair.

For more information on the advantages of using the asTech® Remote Diagnostic Device, contact their master technicians today.

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