What to Do When a Recalibration Fails
by Abby Bowman
Getting a recalibration right isn’t something to leave up to chance, not when lives hang in the balance. But what happens when the recalibration fails?
AGRR magazine spoke with several experts in the field of Advanced Driver Assistance Systems (ADAS) recalibration to find out how to identify and correct failure.
First Things First
A pre-scan is the best way to prevent a recalibration failure, or at least predict that one will occur, says Jacques Navant, technical director of Don’s Mobile Glass in Modesto, California, and president of the Auto Glass Safety Council (AGSC).
“Anybody working on vehicles with ADAS needs to live and die by the pre-scan,” says Navant. “It gives you a credible roadmap of any issues in the vehicle that could cause a recalibration failure.”
That roadmap comes in the form of diagnostic trouble codes (DTC), says Greg Peeters, CEO of Car ADAS Solutions.
“It’s essential to scan the vehicle for any DTCs and to correct those before going any further,” he says.
The DTCs that flag an unsuccessful recalibration don’t have to relate directly to windshield-mounted cameras, says AGSC director of quality and training Jeff Olive. They could include error codes from a vehicle’s braking system, for example.
“If something like that comes up on a pre-scan, technicians should have the car owner take it to the dealership or a mechanic to have the braking issue fixed before working on the glass,” Olive says.
It’s critical to look out for DTCs that directly pertain to recalibration, too.
“A pre-scan will catch an internal camera failure before you get too far into the process,” says Navant.
Problem Solving
The pre-scan doesn’t completely prevent problems, though. When a recalibration does fail, Chris Goff, ADAS trainer at Ultimate Auto Glass & Electronics, says technicians don’t typically have to guess why.
“Usually, the calibration system tablet will say that the recalibration failed. Technicians should see other obvious signs the recalibration failed, like post-inspection DTCs and error lights on the dash,” he says.
That’s when the problem-solving starts. There are a few common reasons for failures. The first, and most frequent, is an uncontrolled environment, says Peeters.
“Often, there’s some kind of inconsistent lighting, reflection, a distraction or something else that could prevent the camera from relearning itself during recalibration,” he says.
The second most common cause is that something went wrong during the recalibration process itself, according to Peeters.
“Incorrect target placement can be fixed without too much trouble. A technician might have misread a measurement or just assumed the measurements were the same across most model years for the same vehicle,” he says.
The second and third most common reasons a recalibration fails, according to Peeters, involve the camera and its line of sight.
“Sometimes the sensor is reinstalled incorrectly after a replacement; it might not have been fully snapped back into the bracket,” he says. “Or, there’s a thumbprint or some other distortion in front of the camera.”
Getting Specific
Goff says the DTCs point to the exact recalibration problem for some vehicle makes and models. Subaru has several different “not good” (NG) failure codes. Goff says the automaker’s technical information system has a chart outlining what each code means and what might have caused the failure.
“Toyota is also good about letting you know if a recalibration worked or not,” says Goff. “Toyota will beep five times on a static recalibration and three times on a dynamic recalibration if it was successful. One short beep or a series of short beeps at the beginning, though, means something is wrong.”
Failure codes offered by some manufacturers aren’t so helpful, though.
“Cadillac just says ‘calibration failed,'” he says. “That’s it.”
Here’s What Happens
Sometimes, a recalibration “fails” because it never happened in the first place. Chris Goff, ADAS trainer at Ultimate Auto Glass & Electronics, provided a real-time example.
“[The first image] popped up on an aftermarket calibration tablet when the technician tried to initiate a recalibration on this Mercedes-Benz,” he says. “Then we got [the second image] after we tried to calibrate again.”
Goff walked the technician through the most common causes of failure. When that still didn’t reveal the problem, Goff looked deeper.
“I noticed even after the tablet displayed the calibration failure message, the vehicle had no error lights,” he says. “A scan of the module revealed no new DTCs, so we determined that calibration never started.”
Goff explains that most aftermarket ADAS tablets have a dedicated path to the ADAS modules in addition to an “all modules” section. The software could malfunction if the coding between the “all modules” side and the separate ADAS side is wrong.
“To test this theory, we created a new ticket with a fresh pre-scan and attempted the calibration through the ‘all modules’ side of the tablet,” he says. “That worked.”
Last Steps
Whether successful or not, Peeters says technicians should always document the results of a recalibration.
“The diagnostic tool should always tell you if the recalibration was successful,” he says. “If you don’t get the message that it was successful and don’t document it, then shame on you.”
That documentation is crucial for a variety of reasons, including obtaining insurance approval for original equipment manufacturer (OEM) glass. It also provides a record in case there’s a problem later.
“Print out or capture the recalibration failure report every time,” Peeters says. “If you have three or four of those after double-checking that everything’s aligned the way that it should be, that’s pretty good documentation for insurance.”
Getting a successful recalibration report doesn’t mean you’re done with the job, adds Navant. “A post-calibration drive is the best way to ensure it was successful,” he says. “Then, do a post-scan to catch any remaining diagnostic codes.”
Peeters adds that technicians must keep multiple factors in mind during that test drive.
“Several of a vehicle’s safety systems use the windshield-mounted camera,” he says. “You have to test all of those systems.”
Systems are becoming more complex, Peeters says, making a test even more crucial.
Abby Bowman is the editor of AGRR magazine. Email her at abowman@glass.com and follow her on LinkedIn.
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