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Another (Different) Diagnostic Debate

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Another Different Diagnostic Debate_0517

Since beginning this column in January 2016, my goal has been to answer the most pressing questions I get from shop operators around the country. Sometimes, it seems I circle back to similar topics fairly often; that’s because I do, and I do it intentionally.

Bottom line, my friends, there are some key issues in our industry that we need to get a handle on to be able to thrive in the years ahead. And these are the very same topics brought to me in my conversations with a lot of you. 

So, here we go for this month: OEM versus aftermarket scan tools. This obviously falls into the bucket of diagnostic scanning topics—and it’s a very crucial one to get out there. 

I hear it all the time, especially from folks that also run (or have worked in) mechanical shops: We use aftermarket scan tools, and they work just fine. And, you know what, that is likely very true. Unless you’re a dealership service center, the majority of mechanical work comes from out-of-warranty vehicles; i.e., older vehicles. The older the vehicle, the less complex its computer systems will be. And, if you’re not working on a vehicle that was in a collision, you don’t have to worry about a lot of advanced systems registering with problems. 

But we’re not talking about performing mechanical work here. By nature, all the vehicles in your shop have been in a collision, and let’s face it, you have the potential to work on the newest vehicles on the market. A brand-new car won’t need service for months—but it could get into a wreck just driving out of the parking lot of the dealer. 

And it’ll wind up at your shop. And you must be able to fix it properly.

I’m guessing you can see where I’m going with my opinion on this issue. With the way the industry has progressed, it is essential to utilize OEM scan tools for all diagnostic scans in your business. There are two main reasons:


1. Access to build data. All OEM scan tools have access to the automaker’s “build data.” The tools use the VIN to access it, and then it deciphers based on that data. It has access to every feature and system, and what that particular vehicle does and does not have. If you don’t have build data, the scan tool is simply guessing on those features, which can lead to what we call “ghost codes” or false codes. To explain, let’s say I scan a vehicle that does not have a blind-spot monitor. The OEM tool will know that it doesn’t have it, so it doesn’t look for that feature. An aftermarket tool doesn’t know, so it will instead “look” for that system. It’ll fail, and because it can’t find it, it’ll offer a code saying the system has an issue—that’s your “ghost code.”


2. Finding small issues caused during the repair. Let’s say you removed a door handle and side mirror on a vehicle to get it off to the paint department, but you drove the vehicle from one spot to another. The aftermarket tool is not going to pick up on that occurring. It simply can’t. The OEM tool will recognize it with a post-repair scan, and be able to tell you if anything needs to be reset simply from having the vehicle operate during that short period without the handle or mirror.


Now, something to keep in mind: Simply purchasing a tool doesn’t mean you automatically have all you need to properly diagnose a vehicle. You must have someone on staff that can both interpret the data that comes from the tool, and can troubleshoot issues that go far beyond a code. A dangerous myth out there is that you simply need tools to read and clear codes. That is simply not true. 

In order to get the most out of your investment in a scan tool, you need someone properly trained to use it, and you need a process in place that allows it to be used effectively within the repair cycle. Who performs the scan? When do they perform it? Who is responsible for delivering the findings to the shop team, to the insurance carriers, to the customer? Who determines when pre-repair scans are needed, as opposed to just a post-repair scan? 

So, my friends, diagnostic scanning is a complex issue, and you need to find ways to make it work in your shop. Look at your work mix, and purchase the tools that make sense for your operation. Train your staff. Create an SOP. The reason this topic keeps coming up is because there isn’t enough being done yet—and many don’t know how to go about it. Make a plan. This needs to move from hot topic to a basic standard. Let’s get it done.

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