OEMs require pre-scans and post-scans on most modern collision repairs. Some shops bill but skip. Here's what a real scan report looks like and how to verify yours actually happened.
Almost every collision repair on a 2018 or newer vehicle should include two diagnostic scans: one before work begins, one after the repair is complete. The OEMs require it. The insurance estimating software includes it. The line shows up on the estimate and on the invoice.
The work behind the line item doesn't always happen.
Some shops bill for scans they didn't run. The customer never sees a scan report, never asks for one, and the $200 line item disappears into the final invoice without anyone verifying the work was performed. It's one of the easiest places in collision repair to invisibly cheat.
Pre-scan vs post-scan
Pre-scan happens at intake, before any repair work begins. The technician connects an OEM-approved scan tool to the vehicle's OBD-II port. The tool pulls every diagnostic trouble code stored in every module on the car, prints a report, and saves it to the repair file.
Pre-scans serve three purposes. They catch pre-existing codes that have nothing to do with the collision (a check-engine light from last month, an old ABS code), establishing a baseline. They identify post-collision codes that aren't visible from outside (a torn airbag harness throwing a code, a knocked-out blind-spot radar, a tire-pressure sensor reset). And they document the vehicle's electronic state at intake, which protects both shop and customer.
Post-scan happens after repair is complete, before final delivery. Same tool, same process. The technician pulls codes again, verifies the codes are clear (or that any remaining codes are non-collision-related and documented), and prints a report.
Post-scans serve two purposes. They verify the repair didn't introduce new codes (a sloppy reinstall throwing a sensor code, a calibration that didn't complete cleanly, a module that needs reprogramming). And they document the vehicle's electronic state at delivery, so the customer can verify the car is electronically intact.
Why the OEMs require it
Manufacturer position statements from Ford, GM, Toyota, Honda, Nissan, and virtually every other major OEM specify that pre-scans and post-scans are required on most modern collision repairs (the same OEM position statements that govern ADAS calibration after a collision). The position statements cite the same reasoning: modern vehicles have dozens of electronic modules, sensors, and systems that interact in ways that can't be assessed visually, and the only way to verify the electronic systems are functioning correctly is to scan them.
A shop that doesn't pre-scan and post-scan is delivering a vehicle whose electronic state hasn't been verified against the OEM specification. The cosmetic repair might be perfect. The electronics might be silently broken.
Why some shops skip the scan
The customer can't easily tell.
Pre-scans take maybe fifteen minutes including the report. Post-scans take similar. A high-volume shop can do them in batches, but they still take time. Time is money, and on a cycle-time-pressured DRP arrangement, the temptation to bill the scan and skip the actual work is real.
Skipping a scan saves the shop time. The customer doesn't notice anything. The car drives fine. The electronics either work or don't, and if they don't, the customer assumes it's something else.
The shop bills the line item. The insurer pays. Nobody asks.
Until the next collision, where the airbag doesn't deploy because the pretensioner module had a stored fault from the previous collision that nobody cleared, and the airbag computer decided not to fire.
What a real scan report looks like
A pre-repair or post-repair scan report has specific elements. If your scan report doesn't include all of these, it might not be a real OEM-procedure scan.
Date and time of the scan. When the scan was performed. Should match the day of intake (for pre-scan) or the day before delivery (for post-scan).
VIN of the vehicle scanned. The full Vehicle Identification Number. This is what proves the scan was actually run on your specific car, not pulled from a template.
Vehicle make, model, year. Sanity check that the scan matches your vehicle.
List of modules queried. Modern vehicles have anywhere from 20 to 100 electronic modules. The scan tool queries each one. The report should list them, often with abbreviations (PCM, BCM, ABS, SRS, RCM, etc.).
Codes found in each module. Either a list of diagnostic trouble codes (DTCs) with descriptions, or a notation that no codes were stored.
Scan tool used. The make and software version of the scan tool. OEM-approved tools (Autel, Snap-On, Bosch, OEM-direct tools) are documented; consumer-grade tools usually aren't.
Technician name or initials. Who ran the scan.
Pre or post designation. Whether this is the pre-repair scan or the post-repair scan.
A real scan report runs anywhere from two pages to ten pages depending on how many codes were found. A fake report (or a template that was filled in without an actual scan) is usually shorter, missing detail in the module list, or missing the VIN match.
How to verify yours actually ran
Three checks:
Ask for the scan report. Both pre-repair and post-repair. The shop should produce them within minutes; they live in the repair file.
Check the VIN on the report. Match it to your vehicle's VIN (on the dashboard near the windshield, on the driver's door jamb). They should be identical.
Check the date on the report. Pre-scan should be on the day of intake (or within a day or two). Post-scan should be within a day or two of delivery. A pre-scan dated three weeks before intake (or with no date) is a template.
If the shop can't produce the reports, can't match the VIN, or can't explain the dates, the scan probably wasn't run. The scan line on your invoice is for work that didn't happen.
What to do if the scan wasn't run
Two options.
Have the scan run now. Even a post-delivery scan is better than no scan. We'll run one on your vehicle for free if you bring it in, and we'll give you the report. If the report turns up codes that should have been caught and cleared during the original repair, you have grounds to go back to the original shop for either a refund of the scan line item or a free re-repair of the missed work.
Dispute the scan charge on the invoice. Either with the shop directly, or with the insurer, or with the Bureau of Automotive Repair. Billing for work not performed is fraud under California law. BAR investigates these complaints when the documentation is clear. The scan charge is one of several places this can hide on a body shop invoice.
Most shops, confronted with the dispute, refund the scan charge without escalation. A few don't, and the BAR complaint is the next step.
The position
The diagnostic scan is one of the lowest-effort, highest-protection items on a collision repair. Real shops run them on every car that comes through. The line item is honestly billed. The reports are delivered to the customer as part of the final paperwork, no questions asked.
If a shop won't give you the scan reports, the scan probably didn't happen. The cosmetic work might be fine. The electronic work, which is most of what a modern car is, hasn't been verified.
The scan report is yours. Ask for it.
If your invoice has a scan line item and you've never seen the report, ask your shop for it today. If they can't produce one or push back, call us at (949) 859-7990 or stop in with the paperwork. We'll tell you whether the charge is legitimate or worth disputing.
The scan report is yours. Ask for it. - Gilbert
Frequently Asked
What is a pre-scan and post-scan after a collision?
A pre-scan is a diagnostic scan run before repair work begins, pulling all stored diagnostic trouble codes from the vehicle's modules. A post-scan is the same scan run after repair is complete to verify the electronics are clean. OEMs require both on most modern collision repairs; they document the vehicle's electronic state at intake and at delivery.
Did my body shop actually run the scan they billed for?
Ask for the scan report. Both pre-repair and post-repair. The shop should produce them within minutes. Check the VIN on the report matches your vehicle, and check the dates match intake and delivery. If the shop can't produce the reports or the details don't match, the scan probably wasn't actually run.
What should be on a scan report?
Date and time of the scan, full VIN, vehicle make/model/year, list of modules queried (usually 20 to 100 modules), diagnostic trouble codes found in each module (or notation that none were stored), scan tool make and software version, technician name or initials, and pre-or-post-repair designation.
Can I refuse to pay for a scan that wasn't run?
Yes. Billing for work not performed is fraud under California law. If your shop can't produce a scan report matching your VIN with appropriate dates, dispute the charge. Most shops refund it without escalation. If they don't, the Bureau of Automotive Repair investigates billing complaints when the documentation is clear.