GM Position Statement

Pre- and Post-Scan of Collision Vehicles

October 2016

General Motors takes the position that all vehicles being assessed for collision damage repairs must be tested for Diagnostic Trouble Codes (DTCs) during the repair estimation in order to identify the required repairs. Additionally, the vehicle must be retested after all repairs are complete in order to verify that the faults have been repaired and new faults have not been introduced during the course of repairs. Even minor body damage or glass replacement may result in damage to one or more safety-related systems on the vehicle. Any action that results in loss of battery-supplied voltage and disconnection of electrical circuits requires that the vehicle is subsequently tested to ensure proper electrical function. Many safety and security-related components, sensors and Electronic Control Units (ECUs) require calibration and/or learns when replaced. These systems must be repaired according to the corresponding GM repair procedures in Service Information (GMSi).

Technology Supported Diagnostic Aids

General Motors states that the method to correctly identify vehicle diagnostic trouble codes (DTCs) is by using the appropriate GM diagnostic software: GDS2 or Tech 2/Tech2Win, each of which can scan a vehicle for all DTCs in one operation. GM diagnostic software is supported by one of the GM approved diagnostic scan tools (MDI or a J2534 device). GM does not recommend the use of other scan tools and cannot guarantee their accuracy. For a list of vehicle covered by these applications, refer to the GM technical document titled Vehicles Supported by GDS2 or Tech2/Tech2Win. GMSi is the factory source for all diagnostic and repair procedures, wiring diagrams and associated repair information. GM Service Programming System (SPS) is the ECU programming application that provides calibration updates and guided learn procedures where required. Any repairs performed without using Genuine GM Parts and not following published GM collision repair procedures may result in erroneous DTCs and expose vehicle owners and occupants to unnecessary risk. GM collision repair information can be accessed for free on or is available through a GMSi subscription.

How to obtain GM diagnostic and flash programming software and service information in North America

TIS2Web is the Internet-based subscription service for GM service information, vehicle calibrations, GDS2 diagnostic software and Tech2 diagnostic software updates. Subscription options and more information on GMSi, SPS and TIS2Web can be found at


Download GM’s Full Position Statement