The Case of the Bracketed Failure
By Jonathan Dickerman
As a mobile technician, I often get calls to give second opinions on vehicles that have failed calibration. This particular request came in from a local body shop, as they had installed a new windshield into a vehicle and want-ed the forward-facing camera calibrated. As the conversation went on, we learned that the vehicle had already been to a local Acura dealer, where they were unable to complete the process. The dealer blamed an aftermarket windshield. The shop then purchased OE glass but wanted a second opinion be-fore they installed it and could no longer file a return.
The vehicle in question was a 2014 Acura RLX fitted with an early lane keep assist system (LKAS) which used the windshield mount-ed camera to monitor the vehicle’s lane position and, if needed, give steering input to make corrections. From a calibration perspective, this vehicle required both static and dynamic calibration, which calls for doing it inside using targets, followed by a dynamic camera aimed at the road.
Upon arrival at the shop, we began with a quick visual inspection, revealing several ADAS-related warnings on the dash. Next, we grabbed our scan tool, the Honda iHDS, and performed a pre-scan, revealing trouble code 11-1: “dynamic camera aiming failed stored in the LKAS module.” The fault code told us that a dealer technician was likely able to perform the static aiming procedure successfully, but the dynamic aiming procedure failed.
An appropriate calibration space was secured, and the OE targets were set up using factory service information. Using the scan tool, the static calibration procedure was performed which resulted in a failure code 3: “Camera angle is in-correct.” At this point our calibration technician hat came off and the diagnostician hat went on.
Fixing a Failure
Step one with a failed static calibration is always to double check your set-up. This means making sure you are using the correct tar-gets and that they are at the proper height and distance from the vehicle as defined in factory service information. In this case, the set-up was correct. Next, we wanted to en-sure that the environmental conditions were correct. The area should be well lit with no windows, lights or objects behind the targets that could be mistaken for them. Just like our set-up, our area met the criteria for a successful calibration.
With the environment and the set-up confirmed to be correct we needed to focus on the vehicle. A visual inspection, along with some quick ride-height measurements, ruled out any suspension issues that could affect camera angle.
Finally, we needed to look at the camera installation, as often times we find that calibration failure is simply a result of cameras that weren’t seated properly in brackets, or that have views obscured by objects or stickers. In this case, the camera was accessed and inspect-ed, revealing no obvious issues with mounting. The camera was fully seated on the aluminum bracket and had a clear view of the targets.
At this point we had a decision to make. Our diagnostics showed that the area, the targets and the camera mounting were all correct, but was this enough to tell the shop owner on the idea that they needed to purchase and install OE glass? If it was the glass, it would be the first vehicle in three years that I was unable to calibrate due to windshield quality.
All indicators pointed to an issue with the glass, but what was the problem? Were we dealing with an optical issue like a wave in the glass? Watching the light reflect off the glass from every possible angle, the glass in front of the camera looked as smooth as, well, glass. How about a bracket issue? Perhaps the bracket was placed improperly on the windshield? Comparing the bracket placement to the OE glass sitting in the office I couldn’t find any measurable discrepancies. Were there any other tools we can utilize to confirm our suspicions? Going back to the miscellaneous test menu in iHDS, there is a function that I have only seen on these early LKAS systems, “Video Output.”
The video output function takes a snapshot from the LKAS camera and transmit the image as a JPEG file to the computer. The image that is output includes rectangles which represent the tolerances for camera positioning. Zooming in on one of the targets, we clearly saw that the target was positioned outside of the tolerance range. Our previous testing confirmed that the target was placed correctly and the vehicle had no suspension issues that could cause the camera misalignment dis-played in the image. This could only be an issue with the placement of the camera bracket, so the wind-shield had to be replaced.
The shop installed the replacement windshield and I returned the following day to perform the calibration. Even when you are 100% certain of your diagnosis, there is always that little bit of anxiety involved in the return trip. The static and dynamic calibrations were both completed successfully, and the LKAS system was proven to operate as designed confirming a successful repair.
I bring this vehicle up for a few reasons. For one, it highlights the importance of going over your work and having a diagnostic strategy in place for when a calibration does fail before condemning a windshield. Second, going back to the snapshot taken by the LKAS camera and using the target stand as reference, we roughly calculated that the rectangle represented a tolerance window of roughly 3- by 5-feet at the targets position of 19-½ feet from the front wheels. This rough calculation put the target approximately one foot above the nominal position. The amount of camera misalignment that was present considering the minute difference in the bracket position highlighted the need for calibration any time the camera has been removed.
Jonathan Dickerman is an advanced mobile diagnostic technician for Sullivan Tire in Taunton, Mass.
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