Diagnostic Trouble Codes
July 22, 2019

Here is automobile repair terminology that you should know.


Automobiles and trucks manufactured within the past five years carry an average of 25-50 onboard computers. These computers control practically every function of your vehicle. As the automobile industry moves through design and technical changes, so do the methods a collision repair facility must undertake to properly repair damaged vehicles. First and foremost, a shop should perform a diagnostic scan of the vehicle’s computer system, searching for Diagnostic Trouble Codes (DTC). This pre-scanning helps the technician identify DTCs in the electrical system of the vehicle and determine if the DTCs are related to the accident or preexisting.

Pre–and post– diagnostic scanning is a step in the auto body repair process that is crucial to be aware of as a consumer. Before and after a repair your shop’s technician should use a vehicle diagnostic computer to scan your vehicle’s internal electronics. This procedure allows us to know if there’s anything wrong in the electrical components before moving forward with the repair, and also before returning the vehicle back to you. The importance of this step has led many vehicle manufacturers to release OEM position statements that recognize the importance of shops performing computer scans. Every automobile manufacturer recommends diagnostic scans on vehicles involved in accidents.

Many of today’s vehicle owners are under the impression that if something is wrong with their vehicle a Malfunction Indicator Light (MIL) will light up on their dash panel. The fact is, not all DTCs will illuminate the MIL. There are numerous DTCs within your car’s electronics that can only be identified through the scanning process. If a vehicle were to leave the shop with overlooked DTCs – it could cause improper performance of the vehicle.

It is the responsibility of your repair facility to follow the original manufacturer’s guidelines when repairing damaged automobiles. Diagnostic scanning before and after the repair process has become an area of dispute between collision repairers and insurance companies where many insurers do not feel that scanning a customer’s computer system is their responsibility therefore, placing the obligation to scan or not to scan on the body shop. Please make sure your collision repair facility is aware of the OEM’S requirement to scan vehicles prior to repair and after the repairs are completed. Your vehicle’s operation and your family’s safety may depend on a properly scanned repair.


Your safety is paramount to us no matter what your insurance company says.