From the Desk of Mike Anderson: Hands-On Testing Shows Limitations of Relying Solely on DTCs or Aftermarket Scan Tools
Written by Mike Anderson, Autobody News
Published November 2, 2020
I’ve had the good fortune recently to spend some time recently working with Nissan/Infiniti as they prepare some new hands-on training they are developing, and it gave me a chance to spend some time scanning and learning about calibrations on their newest vehicles.
That led to a couple of key takeaways that I wanted to share with you here.
The first item I discovered made its way into a six-minute video that can be found on Jake Rodenroth’s LinkedIn page here.
Jake and asTech were also at the Nissan/Infiniti training pilot, and his video demonstrates that shops can’t rely solely on the absence of diagnostic trouble codes (DTCs) as an indication that all advanced driver assistance systems on a vehicle are calibrated and ready to function properly. It also shows why even minor damage to a vehicle is enough to warrant a scan.
“I have a 2020 Nissan Titan, my personal vehicle, with some minor freight damage on the front,” Jake said. “There are no DTCs present for the radar. But because of the damage, the radar is actually off-center. The horizontal alignment is measured in degrees, and the spec is plus or minus 3 degrees. My truck is pointing at negative 3.38. It’s out of spec according to Nissan’s manual. But it hasn’t triggered a DTC.”
That’s why shops need to do a thorough review of a pre-repair scan---not just checking for DTCs---to identify the need for something like that to be adjusted. Don’t rely just on the presence or absence of a DTC to determine an ADAS requirement.
Aside from checking for DTCs, check the “values” of the ADAS components---the horizontal and vertical specifications, for example. Just like a four-wheel alignment, you can’t verify if something is properly aligned unless you verify what it is and what it should be, given any acceptable tolerance. You simply cannot determine if specific ADAS components are within specs on a Nissan or Infiniti vehcile without using a scan tool.
The second thing I confirmed while I was working with Nissan is something I don’t always win friends by saying, and that’s this: What you find when scanning a vehicle absolutely varies depending on whether you are using a factory scan tool or an aftermarket scan tool. We did side-by-side comparisons on four brand new Nissans and a new Infiniti, and every single aftermarket tool we tried failed to connect with at least one or more of each vehicle’s control modules.
On a Sentra, for example, the aftermarket tool we used picked up three control modules. The Nissan scan tool picked up 22. You read that right: 22. The aftermarket tool didn’t get past the gateway to be able to pick up anything more than data from the emissions-related controllers.
There’s also another key distinction. Scanning tools aren’t just about reading a module to determine if there are DTCs. It’s about bidirectional control. Can that tool not just read the data, but can it “talk back” to the vehicle? Can it send that vehicle a command that it reacts to?
“When you do ADAS calibrations, that’s all you’re doing,” Jake said of bidirectional control. “You’re telling the camera, ‘Hey, I’m going to calibrate you, and so I want you to look for a particular pattern.'”
It’s a similar process If you’re doing a radar calibration. You’re using the scan tool to send the module a command to activate the radar. Because otherwise that radar doesn’t even activate until the wheels are turning.
Makers of aftermarket scan tools talk about having “coverage” for a wide swath of vehicles. But does that mean full coverage? Can that tool not just read codes but clear codes? Can it reach all the modules on board?
So while some people don’t like that I point out key differences between factory scan tools and aftermarket, I will challenge them to prove me wrong. I’ll meet you wherever you like with a brand new Nissan and the factory scan tool. You bring whatever aftermarket scan tool you like, and together we’ll do a side-by-side comparison.
That’s not to say there isn’t a place for aftermarket scan tools. It’s just important to recognize the key limitations, and as with any tool, not to presume it can do things that it cannot.
And when it comes to scanning and ADAS calibrations, any such limitations can have serious consequences for the driver and passengers in that vehicle post-repairs.