Pre- and Post-Repair Scanning: Scan Tools for Collision Repair

Pre- and Post-Repair Scanning: Scan Tools Collision Repair

Scanning has become a necessary step to determine whether all the sophisticated electronics and safety features in today’s high-tech vehicles are functioning properly — before and after the repair.

How do you know which is the right scan tool for your shop?


Adapted from Josh Cable’s article in BodyShop Business, a TechShop sister publication


When several OEMs issued position statements on pre- and post-repair diagnostic scanning in 2016, it made an impression on John Mosley, owner of Clinton Body Shop in Clinton and Richland, Mississippi. Mosley said he invested around $17,000 in scan tools and equipment after Fiat Chrysler, GM, Honda, Nissan and Toyota declared that scanning collision-damaged vehicles is a critical element of a proper repair.

“You should repair the car as closely as you possibly can to the OEM repair recommendations,” Mosley explained. “Knowing that almost every manufacturer is recommending scans now, I don’t see how a shop can think that they’ve repaired the car properly if they haven’t scanned it.”

But how do you know which is the right scan tool for your shop? Each tool company provides information in a different layout depending on the type of automotive service they offer. Tools can provide scan reports for average service shops, advanced mechanic shops and/or collision repair shops that require insurance approval before the project begins.

It’s important to do your research before choosing the scan tool that will best fit your repair facility’s needs. You may want to talk to other local shop owners about what works for them, or ask your tool distributor for a loaner tool (or two). Smart shop owners will research to find an affordable scan tool that will fill all their shop needs, then purchase two (or more depending on the number of technicians at the shop) and keep them in the bays for easy access by their technicians.

Nothing New

Scanning is nothing new to automotive repair facilities, which have been dealing with OBD II since 1996. Although the initial intent of onboard diagnostics was to identify malfunctions in emission-related systems and components, the role of diagnostic scanning has broadened over the years. On the mechanical repair side, plugging into the OBD II port has become a standard diagnostic practice. On the collision repair side, scanning has become a necessary step to determine whether all the sophisticated electronics and safety features in today’s high-tech vehicles are functioning properly — before and after the repair.

Vehicles have more technology and electrical components than ever before. A pre- and post-repair scan informs the technician of any trouble codes present, even in cases where there are no MILs on the dash.

Mosley’s shops follow a simple rule of thumb: “Anything that’s hit hard, we’re doing a pre- and post-repair scan.” For vehicles that come in with light damage, his shops will conduct post-repair scans at the very least, according to Mosley.

Clinton Body Shop charges one hour total for a pre- and post-repair scan. At his mechanical rate of $100 an hour, that’s $50 for the pre-repair scan and $50 for the post-repair scan. Mosley knows that scanning isn’t going to be a cash cow for his shops, but he doesn’t view his investment in scanning equipment the same way he looks at buying a framing machine or a paint booth.

“It’s more about doing the right thing,” he said.

Using a tool that provides the pre- and post-scan process is necessary, and even though a shop owner is always looking to increase overall business profit, the customer’s safety is most important factor. That being said, one way to optimize your scan tool investment is to find a tool that performs this process quickly and accurately.

MILs Don’t Tell the Whole Story

Now that his body shops are scanning vehicles, Mosley has become a believer in the importance of scanning. The key reason: Scanning is the only way to identify all of the DTCs stored in the vehicle before the repair, and the only way to know that no DTCs are lingering after the repair.

This is especially true for newer vehicles, which are becoming computers on wheels — complex networks of control modules, sensors, actuators, wires and components that enable advanced driver-assistance systems (ADAS) and other safety and convenience features.

There’s so much technology in today’s vehicles that there aren’t nearly enough MILs to cover all the DTCs that can be triggered by a collision — or by the repair process.

This is why a post-repair diagnostic scan is necessary for any repair involving disconnection of electrical components or replacement of body parts — to confirm that all electronics have been reconnected and recalibrated properly. MILs just don’t tell the whole story.

When Matthew McDonnell, owner of Big Sky Collision Center in Billings, Montana, started scanning vehicles in early 2015, he kept a log of his shop’s repair orders to see if it really was necessary to conduct diagnostic scans on every vehicle. Out of 216 vehicles that the shop scanned over a several-month period, only 14 percent of those with DTCs also had MILs. Out of that 14 percent, about half of the MILs were unrelated to the collision damage — items such as tire-pressure alerts and oil-change reminders.

Put simply, if you’re relying on MILs — or lack thereof — to guide your repair plan, “that means you’re going to be right 7 percent of the time,” McDonnell said. “That’s not good. That’s very unsafe.”

Repair-Planning Processes

The need for pre- and post-repair scanning becomes even more glaring when the latest vehicle models come through a shop’s doors.

For example, the pre-repair scan of a newer vehicle can show it arrived at the shop with 11 DTCs, however, the post-repair scan could show that the vehicle had 41 DTCs. The additional fault codes were caused during the repair process.

By taking a close look at a scan report, shops can see that some faults are from the collision, and some are from electronics that may not have been reconnected or recalibrated properly.

McDonnell saw that basic procedures such as removing a door handle, unplugging a battery or moving a vehicle to the paint area were triggering DTCs.

It’s not always necessary to use the shop’s most expensive scan tool when checking for accidentally triggered DTCs. Shop owners can consider purchasing an additional, affordable scan tool that can perform an automatic scan to confirm if DTCs are present during the repair process. This leaves the more expensive scan tool free for work on more important projects, and keeping the shop running efficiently.

Because Big Sky is able to pinpoint exactly what’s wrong with the vehicle (during the pre-repair scan) and ensure that all the issues have been addressed (during the post-repair scan), scanning has become an integral part of the repair-planning and quality-control processes, McDonnell explained.

“Quality has gone through the roof,” McDonnell said. “And customer comebacks don’t exist anymore.”

With vehicles becoming increasingly digital and electronic, McDonnell believes “the car is speaking to us more than it ever has.”

When the vehicle is speaking through DTCs, Mosley believes that it’s vital to listen. Shops can do that by following the OEMs’ advice to perform pre- and post-repair scans on collision-damaged vehicles, and to make scanning a standard piece of the blueprinting, estimating and quality-control processes.

Editor’s note: The original article appeared in the July 2017 issue of BodyShop Business:


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