TL;DR: GM's official position statement, updated March 9, 2026, requires a pre-scan for diagnostic trouble codes before collision repair estimation begins, and a post-scan after repairs are complete to confirm those faults were resolved and no new ones were introduced. Even minor damage, like a body panel or glass replacement, can affect safety-related systems and require calibration or relearn procedures on sensors and electronic control units. Jupiter Collision Center in Garland, a member of the GM Collision Repair Network, follows this scanning protocol on GM vehicle repairs.
When a vehicle comes into a collision repair shop after even a minor incident, what looks like straightforward sheet metal damage can hide something more complicated underneath. Modern vehicles run on a network of sensors, control modules, and safety systems that all depend on each other, and General Motors has a clear, published position on how repairs should account for that: every GM vehicle undergoing collision repair should get a pre-scan and a post-scan, not just a visual damage assessment.
What GM's Position Statement Requires
GM's position statement, updated March 9, 2026, states that every GM vehicle being evaluated for collision damage should undergo a pre-scan for diagnostic trouble codes (DTCs) during the repair estimation phase, before any physical work begins. After all repairs are complete, a post-scan is required to confirm that the original faults were resolved and that no new faults were introduced during the repair process.
GM is direct about why this matters even on repairs that look minor: damage to body panels or glass can still affect one or more safety-related systems that aren't visible from the outside. Any repair step that disconnects the battery or interrupts electrical circuits also requires follow-up testing to confirm proper electrical function afterward.
Why Electronic Verification Matters on Modern Vehicles
Today's vehicles are effectively rolling computer networks, with sensors, control modules, and electronic control units (ECUs) constantly communicating with each other. A collision impact that seems isolated to one area can still disrupt that network, trigger hidden faults, or affect systems drivers rely on every day, like stability control or advanced driver-assistance features.
Many safety and security-related components, sensors, and ECUs require calibration or a relearn procedure any time they're replaced or disturbed during a repair. GM's guidance points to GMSi as the factory source for diagnostic and repair procedures and wiring diagrams, and to GM's Service Programming System (SPS) for ECU programming, calibration updates, and guided relearn procedures. GM makes its collision repair information available for free through genuinegmparts.com or through a GMSi subscription.
What the Pre-Scan Catches
A pre-scan performed at intake gives a repair shop a clear picture of a vehicle's electronic condition before any physical work starts. This step can surface issues that a visual inspection alone would miss, which supports a more accurate repair estimate from the beginning. It also helps set clearer expectations for the shop, the insurer, and the vehicle owner about what the repair actually involves.
What the Post-Scan Confirms
The post-scan is the final check. It confirms that every system is functioning as designed and that the repair work itself didn't introduce a new problem. This matters most on vehicles with advanced safety technology, where even a small calibration shift can affect how a sensor or camera performs. A documented, successful post-scan gives both the owner and the insurer confidence that the vehicle has been restored as closely as possible to its pre-collision condition.
What This Means for Collision Repair Shops
Shops working on GM vehicles need the right diagnostic equipment, trained technicians who know how to interpret scan results, and enough time built into the repair schedule to complete both scans properly. These steps take extra time upfront, but they protect repair quality and help preserve eligibility for manufacturer warranty coverage. GM's broader collision guidance consistently points toward using genuine parts and approved procedures specifically to avoid safety and warranty issues down the line.
Jupiter Collision Center in Garland is a member of the GM Collision Repair Network, which means its technicians work from GM's documented repair procedures, including the pre- and post-scan requirements outlined in this position statement, on GM vehicle repairs.
What Owners and Insurers Should Expect
Owners may notice diagnostic scanning listed as its own line item on a repair estimate. That's a normal part of a proper repair process rather than an unnecessary add-on, and it's worth asking a shop directly whether pre- and post-scans are part of their standard workflow for any collision repair, not just major structural work.
For owners, the bigger picture is straightforward: a properly repaired vehicle should perform the same as it did before the collision, both mechanically and electronically, and diagnostic scanning is how a shop verifies that rather than assumes it.
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Frequently Asked Questions
Why does GM require pre- and post-collision diagnostic scans?
Modern vehicles rely on interconnected sensors, control modules, and safety systems that a collision can disrupt even when the visible damage looks minor. A pre-scan identifies existing diagnostic trouble codes before repairs begin, and a post-scan confirms those issues were resolved and no new ones were introduced. This ensures the vehicle's safety systems function the same way they did before the collision.
What happens if a shop skips the diagnostic scan on a GM vehicle?
Skipping a pre- or post-scan risks missing hidden faults in safety or driver-assistance systems that aren't visible from the outside. It can also affect warranty eligibility and lead to disputes with insurers later if a problem surfaces that wasn't caught during the repair. GM's position statement specifically notes that any repair involving battery disconnection or interrupted electrical circuits needs follow-up testing.
Does this requirement apply only to major collision repairs?
No. GM's guidance applies to any GM vehicle undergoing collision repair, regardless of how minor the visible damage appears. Body panel or glass damage can still affect safety-related systems that aren't visible during a standard inspection, which is why the scanning requirement isn't limited to structural or major repairs.
Disclaimer: This content is provided for general informational purposes and does not constitute professional or warranty advice. Confirm current GM position statement details with a Jupiter Collision Center advisor.
About the Author
Zach Preddy leads collision repair operations at Jupiter Collision Center in Garland, Texas, a member of the GM Collision Repair Network serving North Texas drivers.
Sources & Further Reading
- GM Parts: Position Statement on Pre- and Post-Collision Diagnostic Scans
- Jupiter Collision Center in Garland, TX
- Why a Chevrolet Is the Right Choice for Texas Roads
Published: May 1, 2026 | Last updated: August 4, 2026